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List of 373 Adjectives That Start with O with Definitions and Examples

by Tim

There are many adjectives that start with O in the English language, and some of them can be found in almost every article. We’ve provided a list of adjectives that begin with the letter O, complete with definitions, synonyms, and examples. When you talk or write, you want to elaborate and effectively transmit the meaning and emotions of your words to the audience.

Adjectives that start with O are classified into eight groups. Positive adjectives, negative adjectives, uncommon and commonly used adjectives are among the categories.

Indeed, the language you use reflects tremendously on the sort of person you are. Using suitable language improves communication and the optimism of others around you. Consider the following adjectives that start with O.

Adjectives add information to the essentials of what we express to others. We have described positive and negative adjectives individually to help you learn new descriptive words that start with O and increase your vocabulary. Let’s get started with the following adjectives beginning with O.

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Common Adjectives That Start with O in Everyday Speech

Check our collection of common adjectives that start with O to describe or alter a noun or pronoun and make your speech or writing unique and interesting. In your daily life, apply these commonly used adjectives starting with O.

1. Ordered

  • Definition: marked with a systematized arrangement
  • Synonyms: arranged, organized, classified
  • Example: Her paper was in an ordered manner.

2. Overall

  • Definition: pertaining to everything and every aspect
  • Synonyms: generally, all-in-all, all-inclusive
  • Example: Our overall result was not good.

3. Oral

  • Definition: being communicated through speech or words
  • Synonyms: spoken, verbal, vocal
  • Example: We have some oral arguments.

4. Ordinary

  • Definition: being usual in character
  • Synonyms: common, normal, average
  • Example: He is an ordinary person.

5. Outbound

  • Definition: being extroverted and openly friendly
  • Synonyms: outgoing, outward, sociable
  • Example: She is an outbound lady.

6. Only

  • Definition: being just that and no more
  • Synonyms: merely, just, single
  • Example: He is the only boy in his family.

7. Offbeat

  • Definition: which is not common and typical
  • Synonyms: unusual, unconventional, uncommon
  • Example: That was an offbeat performance.

8. Old

  • Definition: being of elderly age
  • Synonyms: aged, elderly, mature
  • Example: He is an old person.

9. Oversized

  • Definition: bigger than the usual
  • Synonyms: bulging, floppy, droopy
  • Example: He wears oversized shirts.

10. Oily

  • Definition: containing oil
  • Synonyms: greasy, fatty, buttery
  • Example: He has oily skin.

Positive Adjectives That Start with O

Positive adjectives that start with O are used to describe positive persons, places, and things. Using these noun modifiers, you can express joy, love, and other positive feelings.

1. Open-hearted

  • Definition: marked by displaying sympathy and kindness
  • Synonyms: sympathetic, generous, benignant
  • Example: My boyfriend is a very open-hearted man.

2. Obedient

  • Definition: pertaining to obeying orders, rules, and commands
  • Synonyms: docile, compliant, submissive
  • Example: She is an obedient child.

3. Observable

  • Definition: which is capable of being observed
  • Synonyms: noticeable, discernible, perceptible
  • Example: There were some observable differences.

4. Operational

  • Definition: of which is functional
  • Synonyms: operative, working, functional
  • Example: We should build some operational strategies.

5. Omnipresent

  • Definition: having existence everywhere simultaneously
  • Synonyms: ubiquitous, universal, prevalent, ever-present
  • Example: There is an omnipresent threat of natural disasters.

6. Omnipotent

  • Definition: capable of unlimited power and supremacy
  • Synonyms: almighty, all-powerful, invincible
  • Example: The judges have omnipotent power.

7. Objective

  • Definition: lacking any bias or partiality
  • Synonyms: unbiased, unprejudiced, neutral
  • Example: He is an objective lawyer.

8. Open-minded

  • Definition: having the quality of being perceptive
  • Synonyms: broad-minded, unprejudiced, unbiased, liberal-minded
  • Example: My girlfriend is very open-minded.

9. Opportune

  • Definition: fortunate at a particular time
  • Synonyms: auspicious, timely, advantageous
  • Example: He has arrived at a less opportune moment.

10. Ongoing

  • Definition: which is currently progressing and happening
  • Synonyms: continuing, progressive, advancing
  • Example: We are dealing with some ongoing negotiations.

Negative Adjectives That Start with O

The following is a list of negative adjectives that start with O. We hope this list will assist you in learning negative adjectives beginning with the letter O. Continue to study and make notes on what you’ve learned.

1. Overburdened

  • Definition: being excessively burdened
  • Synonyms: overloaded, overworked, burdened
  • Example: I have overburdened work.

2. Obese

  • Definition: having excessive fat and weight on the body
  • Synonyms: corpulent, fleshy, fat, overweight
  • Example: He is an obese child.

3. Obscene

  • Definition: offensive or shocking
  • Synonyms: shocking, scandalous, vile
  • Example: He made some obscene jokes.

4. Outdated

  • Definition: which is not in date
  • Synonyms: obsolete, outmoded, old
  • Example: She was wearing an outdated shirt.

5. Offensive

  • Definition: marked by insult and repulsion
  • Synonyms: repulsive, ridiculing, obnoxious
  • Example: She used offensive language.

6. Oppressive

  • Definition: marked by the attributes of tyranny
  • Synonyms: dictatorial, autocratic, tyrannical
  • Example: He is an oppressive king.

7. Overactive

  • Definition: characterized by an action that is more than normal
  • Synonyms: frenzied, hyperactive, frantic
  • Example: My little brother is very overactive.

8. Obsolete

  • Definition: out of the trend and norm
  • Synonyms: outdated, outmoded, out-of-date
  • Example: They disposed of old and obsolete machinery.

9. Opposite

  • Definition: completely different; of a contrary kind
  • Synonyms: conflicting, contrasting, incompatible
  • Example: She was on an opposite side.

10. Obtrusive

  • Definition: noticeable or prominent in an unwelcome or intrusive way
  • Synonyms: conspicuous, prominent, noticeable
  • Example: Soldiers were less obtrusive in civilian clothes.

Adjectives That Start with O to Describe a Person

Check out our collection of adjectives that start with O to describe someone. Adjectives describe people’s distinctive features, which are among their most important characteristics. Please make every attempt to integrate O adjectives to describe a person into our daily lives.

1. Omniscient

  • Definition: knowing everything
  • Synonyms: all-knowing, all-wise, all-seeing
  • Example: He is an omniscient writer.

2. Outlandish

  • Definition: being unconventional and odd in conduct
  • Synonyms: bizarre, weird, unusual, strange
  • Example: She is an outlandish lady.

3. Obtuse

  • Definition: annoyingly insensitive
  • Synonyms: stupid, dull, slow-witted
  • Example: The doctor was deliberately obtuse.

4. Outmoded

  • Definition: which is not acceptable
  • Synonyms: unacceptable, outdated, obsolete
  • Example: He is an outmoded boy.

5. Officious

  • Definition: who is actively engaged in work
  • Synonyms: busy, engaged, occupied
  • Example: The security people were very officious.

6. Opinionated

  • Definition: marked by stubbornness in opinions
  • Synonyms: dogmatic, prejudiced, obstinate
  • Example: My sister is a very opinionated girl.

7. Overexcited

  • Definition: marked by excessive excitement
  • Synonyms: hyper, frantic, agitated
  • Example: She became overexcited after seeing me.

8. Orthodox

  • Definition: conforming to old norms and customs
  • Synonyms: conventional, traditional, conservative
  • Example: He is an orthodox man.

9. Odd

  • Definition: marked by peculiar behavior
  • Synonyms: strange, bizarre, weird, eccentric
  • Example: I’m not too fond of her odd behavior.

10. Outspoken

  • Definition: marked by straightforwardness
  • Synonyms: blunt, candid, plain-spoken
  • Example: Anna is a very outspoken lady.

Adjectives That Start with O to Describe a Place

What is the total number of unusual locations you have visited? How would you describe these areas to someone who has never visited them? Consider the following list of describing words beginning with O.

1. Odorous

  • Definition: having or giving off an odor
  • Synonyms: foul-smelling, evil-smelling, smelly
  • Example: There was a dark and odorous cave.

2. Odoriferous

  • Definition: having or giving off a smell
  • Synonyms: aromatic, pungent, savory
  • Example: This land is very odoriferous.

3. Occupied

  • Definition: being used by someone
  • Synonyms: inhabited, tenanted, live in
  • Example: Her room was fully occupied.

4. Opulent

  • Definition: ostentatiously costly and luxurious
  • Synonyms: luxurious, sumptuous, palatial
  • Example: That cafe has an opulent comfort.

5. Outstanding

  • Definition: exceptionally good
  • Synonyms: excellent, marvelous, magnificent
  • Example: This is an outstanding place to live.

6. Open

  • Definition: not closed
  • Synonyms: unlocked, unfolded, unlatched
  • Example: There is open ground in their house.

7. Ornamental

  • Definition: serving or intended as an ornament
  • Synonyms: decorative, fancy, ornate
  • Example: We visited some ornamental lakes.

8. Ornate

  • Definition: elaborately or highly decorated
  • Synonyms: elaborate, decorated, embellished
  • Example: She has an ornate painting in her room.

9. Offshore

  • Definition: at some distance
  • Synonyms: away, shoreline, shoreward
  • Example: He has accounts in an offshore island bank.

10. Official

  • Definition: having the approval or authorization
  • Synonyms: authorized, accredited, approved
  • Example: We have an official right to this land.

Adjectives That Start with O to Describe Emotions

This part of the article contains adjective words that start with O. The human experience includes a bewildering assortment of emotions. You never feel like you can convey them sufficiently to yourself or others. It will undoubtedly be useful to employ adjectives that start with the letter O.

1. Overpowering

  • Definition: extremely strong or intense; overwhelming
  • Synonyms: irresistible, overwhelming, powerful
  • Example: She had a feeling of overpowering sadness.

2. Overjoyed

  • Definition: extremely happy
  • Synonyms: ecstatic, euphoric, thrilled
  • Example: She was overjoyed at my success.

3. Obsessive

  • Definition: of the nature of an obsession
  • Synonyms: all-consuming, consuming, compulsive
  • Example: He is dogged by obsessive jealousy.

4. Offended

  • Definition: resentful or annoyed
  • Synonyms: upset, hurt, wounded
  • Example: She sounded rather offended.

5. Obstinate

  • Definition: stubbornly refusing to change one’s opinion
  • Synonyms: stubborn, headstrong, willful
  • Example: She has obstinate determination to pursue her career.

6. Optimistic

  • Definition: hopeful and confident
  • Synonyms: cheerful, cheery, positive
  • Example: She has an optimistic mood.

7. Objectionable

  • Definition: unpleasant or offensive
  • Synonyms: offensive, unpleasant, disagreeable
  • Example: My brother always asks objectionable questions.

8. Ominous

  • Definition: giving the worrying impression
  • Synonyms: threatening, menacing, baleful
  • Example: She had an ominous silence.

9. Outrageous

  • Definition: shockingly bad or excessive
  • Synonyms: shocking, disgraceful, scandalous
  • Example: I’m not too fond of her outrageous behavior.

10. Obnoxious

  • Definition: extremely unpleasant
  • Synonyms: unpleasant, disagreeable, nasty
  • Example: He was spreading some obnoxious odor.

Descriptive Adjectives That Start with O

Adjectives are often used to describe people because they provide a more detailed and clear understanding. We’ve spoken about descriptive words beginning with O. Continue reading to broaden your vocabulary. Please see our collection of O adjectives for further information.

1. Outgoing

  • Definition: marked with an extrovert
  • Synonyms: extroverted, friendly, sociable
  • Example: My brother is a very outgoing person.

2. Odious

  • Definition: which is offensive and detestable
  • Synonyms: obnoxious, offensive, repulsive, abominable
  • Example: She is a pretty odious character.

3. Overfed

  • Definition: given an exceeding amount of food
  • Synonyms: glutted, stuffed, satiated,
  • Example: There was an overfed baby.

4. Overweight

  • Definition: having more than average weight
  • Synonyms: obese, fleshy, heavy, corpulent
  • Example: He was a stone overweight.

5. Observant

  • Definition: quick to notice
  • Synonyms: alert, sharp-eyed, sharp
  • Example: He is a very observant person.

6. Optimum

  • Definition: which is most suitable and favorable
  • Synonyms: optimal, ideal, desirable
  • Example: He was an optimum candidate for the job.

7. Optional

  • Definition: of personal will and choice
  • Synonyms: elective, voluntary, non-mandatory
  • Example: This is her optional job.

8. Original

  • Definition: of real and innovative character
  • Synonyms: real, authentic, genuine, actual
  • Example: This is her original research work.

9. Obscure

  • Definition: not discovered or known
  • Synonyms: unclear, uncertain, unknown
  • Example: Her name is obscure.

10. Organized

  • Definition: characterized by a structured arrangement
  • Synonyms: arranged, ordered, structured
  • Example: They are a very organized group.

Uncommon Adjectives That Start with O to Improve Your Vocabulary

The following list contains uncommon adjectives that begin with O. How many of these uncommon adjectives beginning with O do you use in regular speech and writing?

1. Oblique

  • Definition: having a sloping direction or position
  • Synonyms: slanting, slanted, sloping
  • Example: We sat on the oblique settee.

2. Overt

  • Definition: which is open and obvious to the senses
  • Synonyms: open, clear, unexposed, undisguised
  • Example: That was an overt act of aggression.

3. Obliging

  • Definition: disposed to obligation and accommodation
  • Synonyms: cooperative, compliant, accommodating
  • Example: She is an obliging employee.

4. Oblong

  • Definition: having an ovate shape
  • Synonyms: oval, elongated, elliptical
  • Example: She had some oblong tables.

5. Oblivious

  • Definition: being inattentive and negligent
  • Synonyms: heedless, unaware, unmindful
  • Example: She became absorbed and oblivious.

6. Overzealous

  • Definition: too enthusiastic and eager
  • Synonyms: overeager, bossy, enthusiastic
  • Example: They were very overzealous fans.

7. Outcast

  • Definition: rejected or ostracized
  • Synonyms: reprobate, tramp, vagrant
  • Example: He can be made to feel outcast and inadequate.

8. Obligated

  • Definition: under an obligation
  • Synonyms: bound, obliged, beholden
  • Example: She is doing an obligated service.

9. Operant

  • Definition: being active and producing an effect
  • Synonyms: functioning, operative, working
  • Example: We have an operant agreement.

10. Opaque

  • Definition: being hazy and difficult to comprehend
  • Synonyms: obscure, incomprehensible, unintelligible
  • Example: She had opaque writing.

Adjectives That Start with O – Full List (373 Words)

We looked at a number of adjectives that begin with the letter O. Every adjective beginning with the letter O is included in the list. This is the most comprehensive list of adjectives that start with O that can be found anywhere on the internet.

  • Ordered
  • Overall
  • Oral
  • Ordinary
  • Outbound
  • Only
  • Offbeat
  • Old
  • Oversized
  • Oily
  • Open-hearted
  • Obedient
  • Observable
  • Operational
  • Omnipresent
  • Omnipotent
  • Objective
  • Open-minded
  • Opportune
  • Ongoing
  • Overburdened
  • Obese
  • Obscene
  • Outdated
  • Offensive
  • Oppressive
  • Overactive
  • Obsolete
  • Opposite
  • Obtrusive
  • Omniscient
  • Outlandish
  • Obtuse
  • Outmoded
  • Officious
  • Opinionated
  • Overexcited
  • Orthodox
  • Odd
  • Outspoken
  • Odorous
  • Odoriferous
  • Occupied
  • Opulent
  • Outstanding
  • Open
  • Ornamental
  • Ornate
  • Offshore
  • Official
  • Overpowering
  • Overjoyed
  • Obsessive
  • Offended
  • Obstinate
  • Optimistic
  • Objectionable
  • Ominous
  • Outrageous
  • Obnoxious
  • Outgoing
  • Odious
  • Overfed
  • Overweight
  • Observant
  • Optimum
  • Optional
  • Original
  • Obscure
  • Organized
  • Oblique
  • Overt
  • Obliging
  • Oblong
  • Oblivious
  • Overzealous
  • Outcast
  • Obligated
  • Operant
  • Opaque
  • Optative
  • Ottoman
  • Oropharyngeal
  • Oecumenic
  • Overcooked
  • Orchestral
  • Orthogonal
  • Oncoming
  • Outraged
  • Offish
  • Occasional
  • Octal
  • Oleaceous
  • Optical
  • Opening
  • Oafish
  • Odiferous
  • Odourless
  • Occidental
  • OK
  • Oxidative
  • Organised
  • Oaten
  • Overfamiliar
  • Operating
  • Oceanic
  • Oversuspicious
  • Offstage
  • Omnifarious
  • Orphaned
  • Omnivorous
  • Oecumenical
  • Operatic
  • Occipital
  • Overheated
  • Onymous
  • Orange
  • Overshot
  • Overbearing
  • Obliterate
  • Otherwise
  • Outermost
  • Overwhelmed
  • Overwrought
  • Operative
  • Organic
  • Opportunistic
  • Oracular
  • Overcrowded
  • Overproud
  • Offhand
  • Openmouthed
  • Obsolescent
  • Obliterated
  • Omissive
  • Oblanceolate
  • Opponent
  • Oceangoing
  • Oleaginous
  • Olympian
  • Overgreedy
  • Overhanded
  • Olfactive
  • Own
  • Overhand
  • Outmost
  • Oriented
  • Open-handed
  • Oppositive
  • Offhanded
  • Orbital
  • Orderly
  • Orgiastic
  • Overindulgent
  • Outlaw
  • Ostensive
  • Outlawed
  • Otherworldly
  • Outward
  • Overhead
  • Owing
  • Oval
  • Ontological
  • Optic
  • Overbusy
  • Overrated
  • Offside
  • Opposing
  • Organicistic
  • Overfull
  • Outdoor
  • Oratorical
  • Opencut
  • Ophthalmic
  • Onomastic
  • Oxidised
  • Ocher
  • Oversewn
  • Ownerless
  • Organismic
  • Orientated
  • Overenthusiastic
  • Overlying
  • Olive
  • Outright
  • Oscine
  • Ossicular
  • Onside
  • Ostentatious
  • Octagonal
  • Opposable
  • Overcautious
  • Overripe
  • Outboard
  • Organismal
  • Obdurate
  • Overaged
  • Oviform
  • Outside
  • Oversolicitous
  • Oddish
  • Ordained
  • Overstuffed
  • Overmodest
  • Oxidizable
  • Orphic
  • Obsessional
  • Over
  • Occlusive
  • Overbold
  • Oozy
  • Oneiric
  • Operose
  • Ovoviviparous
  • Overarm
  • Ornery
  • Overseas
  • Orthopaedic
  • Other
  • Openhearted
  • Overambitious
  • Ontogenetic
  • Oviparous
  • Ossified
  • Olympic
  • Orangish
  • Oversubscribed
  • Organizational
  • Overdelicate
  • Outstretched
  • Odorless
  • Overblown
  • Otiose
  • Overpriced
  • Orthostatic
  • Overgenerous
  • Ocular
  • Overwhelming
  • Overcurious
  • Orthomolecular
  • Occurrent
  • Observing
  • Ostensible
  • Overladen
  • Ovine
  • Olivelike
  • Obovate
  • Owlish
  • Orthopedical
  • Outspread
  • Overdue
  • Omani
  • Occluded
  • Obtainable
  • Overdressed
  • Overworked
  • Ovoid
  • Obstreperous
  • Oleophilic
  • Ochre
  • Outrigged
  • Online
  • Omnidirectional
  • Onetime
  • Ornithological
  • One
  • Overgrown
  • Otic
  • Optimal
  • Overnice
  • Overserious
  • Obligate
  • Osteal
  • Outre
  • Obligatory
  • Orbicular
  • Orwellian
  • Oligarchic
  • Offenseless
  • Overstrung
  • Outcaste
  • Occupational
  • Obligational
  • Overanxious
  • Orthotropous
  • Obstructive
  • Oscitant
  • Omissible
  • Opinionative
  • Opencast
  • Overabundant
  • Oldline
  • Overoptimistic
  • Oaken
  • Opalescent
  • Oversea
  • Obsequious
  • Overqualified
  • Overweening
  • Observational
  • Overlarge
  • Onshore
  • Obvious
  • Opaline
  • Organisational
  • Ovate
  • Outbred
  • Orbitual
  • Oversensitive
  • Orthoptic
  • Ocellated
  • Onerous
  • Oversize
  • Overland
  • Outflowing
  • Obstetric
  • Orthopedic
  • Ossiferous
  • Openhanded
  • Olden
  • Overcredulous
  • Operable
  • Osseous
  • Ossiculate
  • Originative
  • Off
  • Octosyllabic
  • Overcareful
  • Oldish
  • Obliterable
  • Operculated
  • Oncologic
  • Overfond
  • Overprotective
  • Olfactory
  • Overcritical
  • Outclassed
  • Outer
  • Overrefined
  • Overmuch
  • Overnight
  • Oleophobic
  • Old-fashioned
  • Ohmic
  • Octogenarian
  • Omnibus
  • Occult
  • Octangular
  • Opposed
  • Overemotional
  • Oversexed
  • Octuple
  • Overconfident
  • Orotund
  • Oriental
  • Obstetrical
  • Owned
  • Overaggressive
  • Outback
  • Overjealous
  • Opprobrious
  • Orbiculate
  • Obstructed
  • Ovarian
  • Overcast
  • Oblate
  • Overhasty
  • Ototoxic
  • Operculate
  • Onstage
  • Outsized
  • Outlying
  • Ordinal

Final Thoughts on Adjectives That Start with O

Are these adjectives that start with O beneficial in your writing? It will be a big honor if the response is yes. Indeed, all adjectives starting with O mentioned above will play an important role in your vocabulary.

It could be difficult to recall all these adjectives, but you can divide the effort and study at least three adjectives daily. We think that just reading this article will make you feel knowledgeable; imagine how fantastic it would feel if you knew all of the descriptive words that start with O.

You’ve probably noticed how crucial adjectives are in our everyday conversations. As you know, English is a widely spoken language; therefore, these adjectives that start with O might make you seem more professional.

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