Words that start with O
Browse 73 words that start with "O" and obtain a full synonym list for those words. You can use our O-words collection anywhere, as it is completely free to use.
There are 3 2-letter words, 5 3-letter words, 5 4-letter words, 4 5-letter words, 7 6-letter words, and 16 7-letter words that start with "O."
For longer words, there are 10 8-letter words, 9 9-letter words, 5 10-letter words, 5 11-letter words, 1 12-letter word, 1 13-letter word, 1 14-letter word, and 1 15-letter word that start with "O."
2 Letter Words that start with O
OK
Synonyms:
all right, right, right then
Opposites: Refusal, DenialPart of speech: Adjective
OK Continued
Oh
Synonyms:
my, golly, goodness
Opposites: Golly, DarnPart of speech: Interjection
Oh Continued
Or
Synonyms:
alternatively, alternately, instead
Opposites: Nor, Neither, NotPart of speech: Conjunction
Or Continued
3 Letter Words that start with O
Oil
Synonyms:
lubricant, lubrication, grease
Opposites: Water, DrynessPart of speech: Noun
Oil Continued
Odd
Synonyms:
strange, peculiar, weird
Opposites: Normal, Conventional, Ordinary, UsualPart of speech: Adjective
Odd Continued
Own
Synonyms:
be the owner of, possess, be the (proud) possessor of
Opposites: Borrow, RentPart of speech: Verb
Own Continued
Old
Synonyms:
elderly, mature, aged
Opposites: New, ModernPart of speech: Adjective
Old Continued
Off
Synonyms:
away, to a distance, from here
Opposites: On, ConnectedPart of speech: Preposition
Off Continued
4 Letter Words that start with O
Over
Synonyms:
above, on top of, higher than
Opposites: Under, BelowPart of speech: Preposition
Over Continued
Once
Synonyms:
One time, At one time, A single time
Opposites: Twice, Many TimesPart of speech: Adverb
Once Continued
Only
Synonyms:
at most, at best, (only) just
Opposites: Also, NeverPart of speech: Adverb
Only Continued
Okay
Synonyms:
all right, right, right then
Opposites: Unsatisfactory, Unacceptable, InadequatePart of speech: Adjective
Okay Continued
Ouch
Synonyms:
cry, darn, displeasure
Opposites: Pleasure, ReliefPart of speech: Interjection
Ouch Continued
5 Letter Words that start with O
Offer
Synonyms:
provide, put forward, give
Opposites: Withdraw, Refuse, WithholdPart of speech: Verb
Offer Continued
Order
Synonyms:
sequence, arrangement, organization
Opposites: Chaos, DisorderPart of speech: Noun
Order Continued
Other
Synonyms:
Additional, Alternative, Different
Opposites: Same, IdenticalPart of speech: Adjective
Other Continued
Often
Synonyms:
frequently, many times, many a time
Opposites: Seldom, Rarely, NeverPart of speech: Adverb
Often Continued
6 Letter Words that start with O
Output
Synonyms:
production, product, amount/quantity produced
Opposites: Input, IntakePart of speech: Noun
Output Continued
Origin
Synonyms:
beginning, start, origination
Opposites: End, Conclusion, TerminationPart of speech: Noun
Origin Continued
Object
Synonyms:
thing, article, item
Opposites: Approve Accept AcquiescePart of speech: Noun
Object Continued
Obtain
Synonyms:
get, acquire, come by
Opposites: Lose, RelinquishPart of speech: Verb
Obtain Continued
Obsess
Synonyms:
preoccupy, be uppermost in someone's mind, prey on someone's mind
Opposites: Neglect, Disregard.Part of speech: Verb
Obsess Continued
Option
Synonyms:
Choice, Alternative, Selection
Opposites: Obligation, RequirementPart of speech: Noun
Option Continued
Online
Synonyms:
Digital, Internet-based, Connected
Opposites: Offline, DisconnectedPart of speech: Adjective
Online Continued
7 Letter Words that start with O
Outside
Synonyms:
outer/external surface, surface, exterior
Opposites: Inside, InteriorPart of speech: Noun
Outside Continued
Outlook
Synonyms:
point of view, viewpoint, views
Opposites: Narrow-mindedness, PessimismPart of speech: Noun
Outlook Continued
On Time
Synonyms:
punctual(ly), prompt(ly), in time
Opposites: Late, Behind SchedulePart of speech: Adverb
On Time Continued
Ominous
Synonyms:
threatening, menacing, baleful
Opposites: Promising, Auspicious, PropitiousPart of speech: Adjective
Ominous Continued
On Duty
Synonyms:
not working, at leisure, on leave
Opposites: Off Duty, InactivePart of speech: Preposition
On Duty Continued
Of Late
Synonyms:
recently, lately, latterly
Opposites: In The Past, FormerlyPart of speech: Adverb
Of Late Continued
Obscure
Synonyms:
unclear, uncertain, unknown
Opposites: Famous, RenownedPart of speech: Adjective
Obscure Continued
Outline
Synonyms:
silhouette, profile, figure
Opposites: Detail, InundationPart of speech: Noun
Outline Continued
On Fire
Synonyms:
burning, ablaze, blazing
Opposites: Extinguished, ColdPart of speech: Adjective
On Fire Continued
Optimal
Synonyms:
Best, Ideal, Perfect
Opposites: Suboptimal, InefficientPart of speech: Adjective
Optimal Continued
Ongoing
Synonyms:
in progress, under way, going on
Opposites: Finished, Abandoned, IntermittentPart of speech: Adjective
Ongoing Continued
Observe
Synonyms:
notice, see, note
Opposites: Disregard, Ignore, BreakPart of speech: Verb
Observe Continued
Outcome
Synonyms:
result, end result, consequence
Opposites: Cause, InitiationPart of speech: Noun
Outcome Continued
Opinion
Synonyms:
belief, judgement, thought(s)
Opposites: Cluelessness, IgnorancePart of speech: Noun
Opinion Continued
Obvious
Synonyms:
clear, plain, plain to see
Opposites: Imperceptible, Inconspicuous, ObscurePart of speech: Adjective
Obvious Continued
Overall
Synonyms:
all-inclusive, general, comprehensive
Opposites: Individual, ImitedPart of speech: Adjective
Overall Continued
8 Letter Words that start with O
Overlook
Synonyms:
miss, fail to notice, fail to observe
Opposites: Spot, NoticePart of speech: Verb
Overlook Continued
Outgoing
Synonyms:
extrovert, uninhibited, unreserved
Opposites: Reserved, Introverted, WithdrawnPart of speech: Adjective
Outgoing Continued
Outdated
Synonyms:
old-fashioned, out of date, outmoded
Opposites: Current, Modern, FashionablePart of speech: Adjective
Outdated Continued
On Track
Synonyms:
On schedule, On course, On target
Opposites: Off Course, MisdirectedPart of speech: Adjective
On Track Continued
Ordinary
Synonyms:
usual, normal, standard
Opposites: Unusual, Extraordinary, Unique, ExceptionalPart of speech: Adjective
Ordinary Continued
Overview
Synonyms:
survey, outline, sketch
Opposites: Detail, SpecificsPart of speech: Noun
Overview Continued
Obsolete
Synonyms:
out of date, outdated, outmoded
Opposites: Careless, Sloppy, SlapdashPart of speech: Adjective
Obsolete Continued
Obstacle
Synonyms:
barrier, hurdle, stumbling block
Opposites: Advantage, Asset, AidPart of speech: Noun
Obstacle Continued
Original
Synonyms:
first, earliest, primary
Opposites: Latest, LastPart of speech: Adjective
Original Continued
Opposite
Synonyms:
facing, face to face with, across from
Opposites: Similar, IdenticalPart of speech: Adjective
Opposite Continued
9 Letter Words that start with O
Offensive
Synonyms:
insulting, rude, derogatory
Opposites: Complimentary, PolitePart of speech: Adjective
Offensive Continued
Oblivious
Synonyms:
unaware, unconscious, heedless
Opposites: Aware, ConsciousPart of speech: Adjective
Oblivious Continued
Operation
Synonyms:
functioning, working, running
Opposites: Inactivity, IdlenessPart of speech: Noun
Operation Continued
Otherwise
Synonyms:
differently, any other way, at another time
Opposites: Similarly, ConsequentlyPart of speech: Adverb
Otherwise Continued
Organized
Synonyms:
put in order, order, arrange
Opposites: Jumble, DisorganizePart of speech: Verb
Organized Continued
Of Course
Synonyms:
naturally, as might be expected, as you/one would expect
Opposites: Not At All, Definitely NotPart of speech: Adverb
Of Course Continued
Overwhelm
Synonyms:
swamp, submerge, engulf
Opposites: Manageable, CalmingPart of speech: Adjective
Overwhelm Continued
Objective
Synonyms:
impartial, unbiased, unprejudiced
Opposites: Subjective, Biased, Partial, PrejudicedPart of speech: Adjective
Objective Continued
Oh My God
Synonyms:
God Almighty, dear Lord, dear me
Opposites: No One Cares, So WhatPart of speech: Interjection
Oh My God Continued
10 Letter Words that start with O
Opposition
Synonyms:
resistance, hostility, antagonism
Opposites: Support, AgreementPart of speech: Noun
Opposition Continued
Occurrence
Synonyms:
event, incident, happening
Opposites: Rarity, AnomalyPart of speech: Noun
Occurrence Continued
Oppression
Synonyms:
persecution, abuse, maltreatment
Opposites: Freedom, DemocracyPart of speech: Noun
Oppression Continued
Obligation
Synonyms:
duty, commitment, responsibility
Opposites: Freedom, ChoicePart of speech: Noun
Obligation Continued
Optimistic
Synonyms:
cheerful, cheery, positive
Opposites: Pessimistic, Negative, Gloomy, OminousPart of speech: Adjective
Optimistic Continued
11 Letter Words that start with O
Overarching
Synonyms:
All-encompassing, Comprehensive, Encompassing
Opposites: Specific, LimitedPart of speech: Adjective
Overarching Continued
On Approval
Synonyms:
Conditional, Subject to confirmation, Pending approval
Opposites: Without Consent, RejectedPart of speech: Preposition
On Approval Continued
Observation
Synonyms:
watching, monitoring, scrutiny
Opposites: Neglect, InattentionPart of speech: Noun
Observation Continued
Outstanding
Synonyms:
excellent, marvellous, magnificent
Opposites: Mediocre, UnexceptionalPart of speech: Adjective
Outstanding Continued
Opportunity
Synonyms:
chance, lucky chance, good time
Opposites: Adversity, DisadvantagePart of speech: Noun
Opportunity Continued
12 Letter Words that start with O
Overwhelming
Synonyms:
very large, profuse, enormous
Opposites: Underwhelming, MildPart of speech: Adjective
Overwhelming Continued
13 Letter Words that start with O
On The Market
Synonyms:
Available, For sale, For purchase
Opposites: Off The Market, UnavailablePart of speech: Preposition
On The Market Continued
14 Letter Words that start with O
Of The Essence
Synonyms:
vital, essential, indispensable
Opposites: Inessential, Unimportant, Non-essentialPart of speech: Adjective
Of The Essence Continued
15 Letter Words that start with O
On The Contrary
Synonyms:
Conversely, Oppositely, Contrariwise
Opposites: In Agreement, SimilarlyPart of speech: Adverb
On The Contrary Continued