370+ Adjectives That Start with O | Definitions and Examples Included

With adjectives that start with O, you will never run out of words to express your emotions.
The list we have prepared for you below includes hundreds of adjectives that start with O, explained not only with the help of definitions but also with examples for your better understanding as well as synonyms for your vocabulary bank.
With the help of adjectives beginning with O, you will never be in a position where you feel like you are inferior to anyone when it comes to explaining your true emotions in front of an audience.
With the use of descriptive words that start with O, you can enhance your writing skills and stand out among all the different writers of your surroundings. A person who reads more is able to write more, so when reading any piece of writing, try to underline and learn as many adjectives starting with O as possible.
Check out our list of descriptive words to increase your vocabulary bank.
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Most Common Adjectives That Start with O
Top 10 common adjectives that start with O are mentioned below. They are used most commonly. However, adjectives starting with O cannot be fitted under one category only, so we have them divided for you guys under lists dealing with different difficulty level.
1. Ordinary
- Definition: of common position
- Synonyms: general, typical
- Example: Ordinary families cannot afford to have elite luxuries.
2. Organic
- Definition: relating to living organisms
- Synonyms: living, essential
- Example: I used organic hair oil when they were falling badly.
3. Only
- Definition: alone of its or their kind
- Synonyms: sole, exclusive
- Example: I am not the only one who does not believe in fanatics.
4. Open
- Definition: allowing access, passage, or a view through an empty space; not closed or blocked
- Synonyms: unblocked, wide
- Example: I left the door open on purpose.
5. Objective
- Definition: expressing with facts
- Synonyms: fair, open-minded
- Example: Scientists try to be objective and impartial.
6. Orange
- Definition: combination of a group of colors present between red and yellow
- Synonyms: coral, peach
- Example: She is wearing an orange dress.
7. Oily
- Definition: impregnated with oil
- Synonyms: fatty, waxy
- Example: My skin is super oily in summers.
8. OK
- Definition: all right
- Synonyms: good, satisfactory
- Example: The seminar was OK.
9. Opposite
- Definition: present at the alternate side
- Synonyms: contradictory, contrary
- Example: They were in the opposite teams.
10. Outer
- Definition: away from the center
- Synonyms: beyond, outside
- Example: I marked the outer surface of the book with black marker.
Adjectives That Start with O – Beginner Level
When you are starting to learn anything, always start with the beginner level and then slowly build it up to the expert level. This list of adjectives that begin with O is mainly for beginners.
1. Oral
- Definition: spoken rather than written; verbal
- Synonyms: spoken, narrated
- Example: We have our oral test on Monday.
2. Online
- Definition: done with the help of any system connected
- Synonyms: wired, accessible
- Example: I hate my online classes.
3. Outdoor
- Definition: consisting of no roof
- Synonyms: casual, open-air
- Example: We attended a huge outdoor wedding last Friday.
4. Occasional
- Definition: made for any certain occasion
- Synonyms: irregular, casual
- Example: Liam plays the occasional game of tennis.
5. Optional
- Definition: not important to be done
- Synonyms: available, extra
- Example: English as well as Urdu are compulsory subjects for all students, but art and music are optional.
6. Ongoing
- Definition: in process
- Synonyms: growing, developing
- Example: Our midterm project is ongoing.
7. Opening
- Definition: coming at the beginning of something
- Synonyms: initial, starting
- Example: Her opening remarks were quite exquisite.
8. Outward
- Definition: of, on, or from the outside
- Synonyms: exterior, obvious
- Example: The chair was to be put in the outward lawn.
9. Own
- Definition: used to express ownership
- Synonyms: individual, owned
- Example: They cannot handle their own kids.
10. Oversensitive
- Definition: tend to offended easily
- Synonyms: prickly, fractious
- Example: Maryam is very oversensitive and weak.
Adjectives That Start with O – Medium Level
Adjective words that start with O at the medium level come after the common and beginner levels. Following are some medium level adjectives that start with the letter O.
1. Observable
- Definition: capable of standing out
- Synonyms: noticeable, apparent
- Example: Liam’s motives are rarely observable.
2. Oncoming
- Definition: coming closely in time or place
- Synonyms: coming, approaching
- Example: A truck was struck by an oncoming vehicle.
3. Opposing
- Definition: placed against something
- Synonyms: adverse, anti
- Example: I’ve been expected to arbitrate between the opposing sides.
4. Offside
- Definition: on the incorrect side
- Synonyms: wrong, unsuitable
- Example: Leonardo Messi was beaten by an offside goal.
5. Obvious
- Definition: easily apprehended
- Synonyms: clear, distinct
- Example: Her obvious popularity made her feel good.
6. Official
- Definition: having the approval or authorization
- Synonyms: formal, proper
- Example: Sheela still has not gotten her official account verified.
7. Oversized
- Definition: much bigger than the standard size
- Synonyms: huge, giant
- Example: I like buying oversized tees.
8. Operative
- Definition: functioning or having effect
- Synonyms: usable, active
- Example: The project is still operative and under strict observation.
9. Outside
- Definition: present on the outer side
- Synonyms: foreign, external
- Example: Mary put the outside lights on.
10. Overpriced
- Definition: too expensive
- Synonyms: posh, luxurious
- Example: They spent the night in an overpriced hotel.
Adjectives That Start with O – Hard Level
So, did it freak you out when you realized now you have reached the hard level? But, nothing to worry about, the describing words beginning with O on the hard level are definitely not impossible.
1. Odorless
- Definition: without any fragrance
- Synonyms: scentless, un-aromatic
- Example: Nitrogen is not a colorless, odorless gas.
2. Offstage
- Definition: unable to be seen by the audience
- Synonyms: casual, unsanctioned
- Example: She was the winner of offstage dancing.
3. Optical
- Definition: in relation to science of visual sensing
- Synonyms: visual, seeing
- Example: Maria has an optical defect and she got rejected for the job of air hostess.
4. Occupied
- Definition: busy and active
- Synonyms: engaged, active
- Example: She remained occupied in work.
5. Opposable
- Definition: capable of being placed against remaining digits of a hand
- Synonyms: opposite
- Example: Humans are known to have an opposable thumb.
6. Offshore
- Definition: present at very far away from the shore
- Synonyms: seaward
- Example: They sailed to an offshore island last week.
7. Obliging
- Definition: always ready to give favors
- Synonyms: willing, cheerful
- Example: I have an obliging neighbor who helped me a lot.
8. Ominous
- Definition: suggesting that something unpleasant is likely to happen
- Synonyms: menacing, foreboding
- Example: The engine had been making an ominous sound all the way back home.
9. Outstretched
- Definition: reaching out as far as possible
- Synonyms: extended, outspread
- Example: She passed a drink to the little girl’s outstretched hand.
10. Overrated
- Definition: rated or valued too highly
- Synonyms: exaggerated, over-promoted
- Example: She’s an overrated player and has accomplished little.
Adjectives That Start with O – Expert Level
Expert level of O adjectives come right after the hard level of descriptive words beginning with O, but just with a slightly increased complexity level. TRUST ME, YOU ARE DOING A GREAT JOB.
1. Omnivorous
- Definition: greedily taking in everything
- Synonyms: greedy, rapacious
- Example: Humans are very omnivorous.
2. Organizational
- Definition: of relating to an organization
- Synonyms: managerial, administrative
- Example: Our Company is looking for a person with organizational skills.
3. Observant
- Definition: paying close attention
- Synonyms: attentive, mindful
- Example: Naila’s observant mindset and eyes took in every detail.
4. Obsolete
- Definition: no longer in fashion
- Synonyms: archaic, antique
- Example: Radio became obsolete when electric lighting was invented.
5. Opaque
- Definition: hard to see clearly
- Synonyms: blurred, frosty
- Example: The jars were filled with a pale opaque liquid.
6. Outlawed
- Definition: anyone or anything under a ban
- Synonyms: banned, illegal
- Example: Weed just recently got outlawed.
7. Outright
- Definition: open and direct
- Synonyms: direct, complete
- Example: Unfortunately, he got an outright refusal.
8. Overqualified
- Definition: having more education than asked for
- Synonyms: trained, knowledgeable
- Example: Little did he know that he would be considered overqualified for the job rather than underqualified.
9. Overactive
- Definition: excessively involved in physical activities
- Synonyms: wild, hyperactive
- Example: Overactive kids are mostly of rough nature.
10. Overt
- Definition: subject to viewing something
- Synonyms: apparent, clear
- Example: I would like to get an overt idea over the concept.
Positive Adjectives That Start with O
Positive adjectives that start with O are specifically listed down for you to describe the positive aspects of anything or anyone you are impressed with, without any second thoughts.
1. Optimal
- Definition: very much satisfactory
- Synonyms: excellent, best
- Example: Mike keeps his car’s engine tuned for optimal performance.
2. Original
- Definition: present or existing from the beginning; first or earliest
- Synonyms: unique, novel
- Example: He sold his original painting for around 300K.
3. Optimistic
- Definition: hopeful and confident about the future
- Synonyms: bright, cheering
- Example: Zahra is very optimistic about her chances of winning a gold medal.
4. Openhanded
- Definition: very generous
- Synonyms: charitable, giving
- Example: Martha’s is known to be a very openhanded, generous person.
5. Openhearted
- Definition: very frank in nature
- Synonyms: blunt, direct
- Example: They gave us an openhearted welcome.
6. Opportune
- Definition: suited perfectly for any position
- Synonyms: apt, lucky
- Example: Thomas and Hardy couldn’t have arrived at a less opportune moment.
7. Organized
- Definition: in a proper manner
- Synonyms: arrange, systematic
- Example: The conference was very well organized.
8. Ornamental
- Definition: serving as an archaic
- Synonyms: ornate, fancy
- Example: The knobs on each side of the door are purely ornamental.
9. Outstanding
- Definition: to be very notable
- Synonyms: eminent, owing
- Example: Jennifer’s singing performance was outstanding.
10. Opulent
- Definition: marked by wealth
- Synonyms: lavish, deluxe
- Example: We stayed at an opulent hotel with good management.
Negative Adjectives That Start with O
Annoyed by anything? We got you. These words, well known as negative adjectives that start with O, are only meant for your rescue from the worst situations possible. Use them in your routine and thank us later.
1. Off
- Definition: not of routine
- Synonyms: bad, tainted
- Example: Even the supreme actors have off days.
2. Outrageous
- Definition: crossing the limits
- Synonyms: barbaric, horrible
- Example: Fuel prices these days are just outrageous.
3. Oppressive
- Definition: very severe
- Synonyms: brutal, harsh
- Example: The marital situation of newly-wed couple has grown increasingly oppressive.
4. Objectionable
- Definition: arousing distaste or opposition
- Synonyms: obnoxious, deplorable
- Example: I found his opinion really objectionable.
5. Obscure
- Definition: hidden by suspense
- Synonyms: cryptic, mysterious
- Example: Lionel’s answers were considered obscure and confusing to the class fellows.
6. Obtuse
- Definition: lacking intellect
- Synonyms: dense, dumb
- Example: George wondered if his teacher was being deliberately obtuse.
7. Offended
- Definition: causing discomfort
- Synonyms: angry, hurt
- Example: Cecilia sounded rather offended than impressed.
8. Offbeat
- Definition: unconventional; unusual
- Synonyms: weird, unorthodox
- Example: Aliya has an offbeat and irritating kind of sense of humor.
9. Outlandish
- Definition: being bizarre
- Synonyms: eccentric, odd
- Example: She fills her books with outlandish characters.
10. Obnoxious
- Definition: vulnerable to something harmful
- Synonyms: nasty, loathsome
- Example: Nobody wanted to talk to the obnoxious man.
Adjectives That Start with O to Describe a Person
As a person, you have a balanced set of positive and negative qualities. When someone likes something about someone, they will definitely use positive adjectives that start with O to describe someone but if they think opposite of them, they will make use of negative O adjectives to describe a person.
1. Old
- Definition: enduring from a past era
- Synonyms: aged, gray
- Example: Mr. William is a very old and respected man.
2. Odd
- Definition: not of very regular nature
- Synonyms: strange, unusual
- Example: Mr. Darcy always behaves in an odd manner.
3. Offensive
- Definition: ready for an attack
- Synonyms: abusive, horrible
- Example: Hadley told some really offensive jokes in a very casual way.
4. Obsessive
- Definition: involvement in something without any boundary
- Synonyms: enslaving, addictive
- Example: My mother is obsessive about punctuality.
5. Obedient
- Definition: willing to comply with
- Synonyms: attentive, docile
- Example: Elizabeth is an obedient lady.
6. Obese
- Definition: having unnecessary body fat
- Synonyms: gross, fleshy
- Example: Obese patients are advised to change their diet.
7. Outspoken
- Definition: expressive without any set back
- Synonyms: blunt, vocal
- Example: Mr. Jack was one of the best outspoken critics of the previous government.
8. Odious
- Definition: worthy of hatred
- Synonyms: abominable, loathsome
- Example: Malika is an odious person and nobody likes her.
9. Obscene
- Definition: awful to the senses
- Synonyms: bawdy, improper
- Example: Bradford made an obscene gesture.
10. Orthodox
- Definition: relating to conservative religious groups
- Synonyms: admitted, authoritative
- Example: Most orthodox scientists however dismiss this as complete nonsense.
Adjectives That Start with O – Full List (370+ Words)
Here is a complete list of adjectives that start with O including what we have discussed above. Go through them once, it will help you revise them all in one go.
- Ordinary
- Organic
- Only
- Open
- Objective
- Orange
- Oily
- OK
- Opposite
- Outer
- Oral
- Online
- Outdoor
- Occasional
- Optional
- Ongoing
- Opening
- Outward
- Own
- Oversensitive
- Observable
- Oncoming
- Opposing
- Offside
- Obvious
- Official
- Oversized
- Operative
- Outside
- Overpriced
- Odorless
- Offstage
- Optical
- Occupied
- Opposable
- Offshore
- Obliging
- Ominous
- Outstretched
- Overrated
- Omnivorous
- Organizational
- Observant
- Obsolete
- Opaque
- Outlawed
- Outright
- Overqualified
- Overactive
- Overt
- Optimal
- Original
- Optimistic
- Openhanded
- Openhearted
- Opportune
- Organized
- Ornamental
- Outstanding
- Opulent
- Off
- Outrageous
- Oppressive
- Objectionable
- Obscure
- Obtuse
- Offended
- Offbeat
- Outlandish
- Obnoxious
- Old
- Odd
- Offensive
- Obsessive
- Obedient
- Obese
- Outspoken
- Odious
- Obscene
- Orthodox
- Ovate
- Overseas
- Oafish
- Obovate
- Occluded
- Olive
- Overhasty
- Overrefined
- Organised
- Overweening
- Overexcited
- Operating
- Oaten
- Octogenarian
- Omniscient
- Outspread
- Officious
- Ostensible
- Outmoded
- Overnight
- Orphic
- Occidental
- Orgiastic
- Opinionated
- Orthomolecular
- Overaggressive
- Oversewn
- Obligational
- Opaline
- Oblique
- Onomastic
- Opalescent
- Outgoing
- Owned
- Omissive
- Oscine
- Ontological
- Occupational
- Obstinate
- Oriented
- Oviparous
- Outboard
- Oropharyngeal
- Opportunistic
- Obligatory
- Overweight
- Omnipresent
- Overgenerous
- Oldish
- Oratorical
- Overcooked
- Onside
- Overdressed
- Oecumenic
- Olfactive
- Obtrusive
- Overproud
- Osseous
- Overaged
- Opencast
- Orderly
- Omnipotent
- Octosyllabic
- Overgreedy
- Open-hearted
- Octal
- Oxidative
- Outraged
- Olfactory
- Orphaned
- Obstructed
- Obligate
- Orthotropous
- Oblanceolate
- Ototoxic
- Orotund
- Overwhelmed
- Overcareful
- Overambitious
- Overfamiliar
- Overcautious
- Orwellian
- Outcast
- Obligated
- Onstage
- Overemotional
- Organisational
- Overheated
- Onymous
- Oriental
- Overcurious
- Opprobrious
- Overserious
- Otherworldly
- Outdated
- Oleaceous
- Oval
- Olympian
- Odoriferous
- Overbusy
- Overblown
- Occipital
- Oxidised
- Opencut
- Orthogonal
- Obliterated
- Oblate
- Ottoman
- Oceangoing
- Oversize
- Operational
- Overcrowded
- Overhand
- Outmost
- Overhead
- Open-handed
- Oceanic
- Obstetrical
- Ophthalmic
- Occult
- One
- Oligarchic
- Oppositive
- Ocular
- Omissible
- Onerous
- Overladen
- Oversuspicious
- Orbiculate
- Obliterate
- Oddish
- Oviform
- Overstuffed
- Ossiculate
- Obsequious
- Obstreperous
- Oncologic
- Obsessional
- Organismic
- Orientated
- Outcaste
- Ossiferous
- Ovarian
- Ohmic
- Ostentatious
- Ocher
- Operant
- Observing
- Offenseless
- Obdurate
- Otherwise
- Offish
- Oversolicitous
- Ordained
- Oleophilic
- Overshot
- Overstrung
- Opponent
- Ostensive
- Optative
- Olivelike
- Oozy
- Orthopaedic
- Overcast
- Obstetric
- Outsized
- Ordinal
- Oneiric
- Osteal
- Overripe
- Octagonal
- Operose
- Owing
- Orangish
- Outbred
- Ornithological
- Overenthusiastic
- Outclassed
- Old-fashioned
- Overdelicate
- Overjoyed
- Otic
- Outermost
- Outlying
- Orchestral
- Overwhelming
- Oblong
- Overbold
- Orbital
- Overbearing
- Ovine
- Otiose
- Owlish
- Ornate
- Overprotective
- Overdue
- Overwrought
- Overgrown
- Octuple
- Overworked
- Ovoid
- Operatic
- Ordered
- Ochre
- Obliterable
- Omnidirectional
- Outrigged
- Opinionative
- Ownerless
- Ossicular
- Overfed
- Ontogenetic
- Overnice
- Odorous
- Overburdened
- Outbound
- Oleaginous
- Orbicular
- Orbitual
- Octangular
- Odiferous
- Overhanded
- Onetime
- Obstructive
- Oscitant
- Odourless
- Ocellated
- Overarm
- Overabundant
- Overoptimistic
- Oaken
- Overfull
- Onshore
- Operculated
- Outre
- Offhand
- Obtainable
- Operable
- Other
- Overjealous
- Ornery
- Obsolescent
- Oversubscribed
- Omani
- Overland
- Orthoptic
- Overmodest
- Occlusive
- Oracular
- Organismal
- Overpowering
- Overcredulous
- Overall
- Overlying
- Open-minded
- Originative
- Overconfident
- Oxidizable
- Optic
- Overzealous
- Overfond
- Outlaw
- Occurrent
- Overcritical
- Olympic
- Oecumenical
- Overmuch
- Oleophobic
- Organicistic
- Oldline
- Omnibus
- Overindulgent
- Overlarge
- Opposed
- Openmouthed
- Orthostatic
- Observational
- Outflowing
- Olden
- Omnifarious
- Over
- Outback
- Offhanded
- Oblivious
- Orthopedical
- Ovoviviparous
- Optimum
- Ossified
- Oversea
- Operculate
- Orthopedic
- Oversexed
- Overvaliant
- Overanxious
Final Thoughts on Adjectives That Start with O
Our brain is capable of playing games with us, especially when we want to say something but fails to. As mentioned above, all the adjectives that start with O, are purposely meant for your good vocabulary.
These adjectives that start with O will be able to help out in different situations. Either irritated by something or if you are extremely impressed by anyone’s quality, adjectives starting with O will be there for you in multiple situations to express your deepest of emotions on the right time, in the right manner.
These descriptive words that start with O, will never abandon you in any situation, you can mark my word. Here, it all comes to an end. NO, no, not your thirst for more and more knowledge. You have a long way to go. There are more adjectives on our website. Do check them out.