certain

1 known but not named a certain person told me that today is your birthday Synonyms anonymous, given, one, some, unidentified, unnamed, unspecified Related Words particular, specific Near Antonyms known, named, specified

2 having or showing a mind free from doubt I'm certain that they'll arrive on time Synonyms assured, clear, cocksure, confident, doubtless, implicit, positive, sanguine, sure Related Words self-assured, self-conceited, self-confident; decisive, resolute, unfaltering, unhesitating, unquestioning, unwavering Near Antonyms hesitant, indecisive, vacillating, wavering; diffident, unassuming Antonyms doubtful, dubious, uncertain, unsure

3 having been established and usually not subject to change a certain percentage of the profits will go to charity Synonyms fixed, determinate, final, firm, flat, frozen, hard, hard-and-fast, inexpugnable, set, settled, stableRelated Words nonadjustable, noncancelable, nonnegotiable, unchangeable; constant, steady, unchanging, uniform, unwavering; definite, exact, explicit, specific; given, stated, stipulated; dependable, good, reliable, responsible, safe, solid, sure, tried, tried-and-true, true, trustworthy, trustyNear Antonyms adjustable, changeable, negotiable; indefinite, open-ended, unspecified; capricious, changeful, flickery, fluctuating, fluid, inconstant, mercurial, mutable, temperamental, uncertain, unpredictable, unsettled, unstable, unsteady, variable, volatile

4 impossible to avoid or evade as he got older, the athlete began to feel the certain effects of the aging process on his body Synonyms inevitable, ineluctable, ineludible, inescapable, necessary, sure, unavoidable, unescapableRelated Words decided, definite, settled; likely, possible, probable; destined, fated, foreordained, predestined, predetermined, preordained; inexorable, relentless, unremitting, unstoppableNear Antonyms preventable (also preventible); doubtful, dubious, questionable, shaky, unclear; undecided, unsettled; undependable, unreliable; improbable, unlikelyAntonyms avoidable, evadable, uncertain, unsure

5 not likely to fail chicken soup is grandma's certain cure for pretty much whatever ails you Synonyms can't-miss, infallible, fail-safe, sure, surefire, unfailingRelated Words dependable, reliable; deadly, unerringNear Antonyms doubtful, questionable, uncertainAntonyms fallible

6 not capable of being challenged or proved wrong up to this point there's been no certain evidence that a crime has been committed Synonyms accomplished, irrefutable, inarguable, incontestable, incontrovertible, indisputable, indubitable, irrefragable, positive, sure, unanswerable, unarguable, unchallengeable, undeniable, unquestionableRelated Words unambiguous, unequivocal; absolute, clear, conclusive, decisive, definite, hands-down; uncontested, uncontradicted, undisputed, unquestionedNear Antonyms controversial, debated, disputed; doubtful, dubious, iffy, inconclusive, indecisive, uncertain; ambiguous, equivocal; academic (also academical), hypothetical, speculative, theoretical (also theoretic)Antonyms answerable, arguable, contradictable, controvertible, debatable, disputable, doubtable, moot, negotiable, problematic (also problematical), questionable, refutable