Definitions

certain

[sur-tn] / ˈsɜr tn /

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confident adj.
undoubtable, valid adj.
fixed adj.
referring to a specifically known amount adj.

ADJECTIVE

confident

Synonyms

STRONGEST

convinced positive sure

WEAK

assertive assured believing calm cocksure questionless sanguine satisfied secure self-confident unconcerned undisturbed undoubtful undoubting unperturbed untroubled

Antonyms

STRONGEST

doubtful uncertain unsure

WEAK

doubting dubious faltering hesitant unconfident undecided

ADJECTIVE

undoubtable, valid

Synonyms

STRONGEST

absolute clear definite genuine positive real safe sure true undeniable

WEAK

ascertained authoritative conclusive confirmable demonstrable destined determined establishable evident firm fixed guaranteed having down pat in the bag incontrovertible indubitable infallible irrefutable known on ice plain predestined provable reliable salted away set sound supreme trustworthy unambiguous undoubted unequivocal unerring unmistakable verifiable

Antonyms

STRONGEST

counterfeit doubted doubtful false invalid uncertain unreal unsure vague

WEAK

questionable unpredictable unreliable

ADJECTIVE

fixed

Synonyms

STRONGEST

definite sure

WEAK

assured bound certified concluded decided determined ensured established guaranteed insured set settled stated stipulated warranted

Antonyms

STRONGEST

indefinite uncertain

WEAK

doubtful dubious questionable unfixed unpredictable unreliable

ADJECTIVE

referring to a specifically known amount

Synonyms

STRONGEST

individual numerous particular precise special specific specified various

WEAK

a couple a few defined divers express many marked one regular several singular some sundry upwards of

Antonyms

STRONGEST

common general imprecise indefinite inexact usual

WEAK

questionable uncertain undecided unpredictable unsure

Usage

What are other ways to say certain?

Certain, one of a handful of adjectives indicating full belief and trust that something is true, suggests that there are definite reasons that have freed one from doubt. Confident emphasizes the strength of the belief or the certainty of expectation felt. Positive implies emphatic certainty, which may even become overconfidence or dogmatism. Sure, the simplest and most general term, expresses mere absence of doubt.

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

certain

MSF also raised concerns over "excessive concentration" of efforts in certain areas at the expense of other areas where needs were more urgent.

From BBC ● Nov. 12, 2026

These add-ons might help in certain scenarios, but the payouts apply to very specific events and conditions, Kemp said.

From MarketWatch ● Nov. 12, 2026

Stripping out certain one-time items, adjusted per-share earnings were $4.16, ahead of the $4.06 anticipated by analysts, according to FactSet.

From The Wall Street Journal ● Nov. 12, 2026