1. (adj)certain(a) definite but not specified or identified Antonyms: undependable, flukey, unreliable, contingent, iffy, chancy, uncertain, careless, up in the air, indefinite, fluky
2. (adj)certain(p), sure having or feeling no doubt or uncertainty; confident and assured Antonyms: iffy, unreliable, chancy, undependable, flukey, careless, fluky, up in the air, uncertain, contingent, indefinite
3. (adj)certain(p) established beyond doubt or question; definitely known Antonyms: undependable, indefinite, flukey, up in the air, chancy, uncertain, iffy, unreliable, fluky, careless, contingent
4. (adj)certain, sure certain to occur; destined or inevitable Synonyms: certain(p), sealed, certain(a), trusted, indisputable, sure, certain Antonyms: indefinite, fluky, contingent, flukey, undependable, iffy, unreliable, careless, chancy, uncertain, up in the air
5. (adj)sealed, certain established irrevocably Synonyms: certain(p), sealed, sure, certain(a), plastered, certain Antonyms: up in the air, indefinite, careless, unreliable, iffy, undependable, uncertain, flukey, chancy, fluky, contingent
6. (adj)certain, sure reliable in operation or effect Synonyms: certain(p), sealed, certain(a), trusted, indisputable, sure, certain Antonyms: chancy, unreliable, flukey, careless, iffy, up in the air, fluky, undependable, contingent, uncertain, indefinite
7. (adj)certain, sure exercising or taking care great enough to bring assurance Synonyms: certain(p), sealed, certain(a), trusted, indisputable, sure, certain Antonyms: fluky, indefinite, chancy, iffy, undependable, careless, up in the air, unreliable, contingent, flukey, uncertain
Synonyms, Thesaurus & Antonyms of 'certain'
English Synonyms and Antonyms
1. certain That is authentic which is true to the facts; that is genuine which is true to its own claims; as, authentic history; genuine money. A 'genuine' work is one written by the author whose name Synonyms: authentic, accepted, certain, original, sure, accredited, current, real, true, authoritative, genuine, received, trustworthy, authorized, legitimate, reliable, veritable Antonyms: apocryphal, counterfeit, exploded, false, spurious, baseless, disputed, fabulous, fictitious, unauthorized
Synonyms for certain 
