adjective
conditional, experimental
Synonyms: acting, ad interim, conjectural, contingent, dependent, iffy, indefinite, makeshift, not final, not settled, on trial, open for consideration, probationary, provisional, provisionary, provisory, speculative, subject to change, temporary, test, trial, unconfirmed, undecided, unsettled
Antonyms: certain, decisive, definite, final, sure
adjective
indefinite, uncertain
Synonyms: backward, cautious, diffident, disinclined, doubtful, faltering, halting, hesitant, irresolute, reluctant, timid, undecided, unsure, vacillating, vacillatory, wobbly
Antonyms: certain, conclusive, definite, sure