Antonyms of adj tentative

2 senses of tentative

Sense 1
probationary, provisional, provisionary, tentative -- (under terms not final or fully worked out or agreed upon; "probationary employees"; "a provisional government"; "just a tentative schedule")

INDIRECT (VIA conditional) -> unconditional, unconditioned -- (not conditional; "unconditional surrender")

Sense 2
doubtful, tentative -- (unsettled in mind or opinion; "drew a few tentative conclusions")

INDIRECT (VIA unsettled) -> settled -- (established or decided beyond dispute or doubt; "with details of the wedding settled she could now sleep at night")

Similarity of adj tentative

2 senses of tentative

Sense 1
probationary, provisional, provisionary, tentative -- (under terms not final or fully worked out or agreed upon; "probationary employees"; "a provisional government"; "just a tentative schedule")
       => conditional (vs. unconditional) -- (imposing or depending on or containing a condition; "conditional acceptance of the terms"; "lent conditional support"; "the conditional sale will not be complete until the full purchase price is paid")

Sense 2
doubtful, tentative -- (unsettled in mind or opinion; "drew a few tentative conclusions")
       => unsettled (vs. settled) -- (still in doubt; "an unsettled issue"; "an unsettled state of mind")