Antonyms of adj unthinkable

1 sense of unthinkable

Sense 1
unthinkable (vs. thinkable) -- (incapable of being conceived or considered)

thinkable (vs. unthinkable) -- (capable of being conceived or imagined or considered)
        => cogitable, ponderable -- (capable of being thought about; "space flight to other galaxies becomes more cogitable")
        => conceivable, imaginable -- (capable of being imagined; "that is one possible answer")
        => presumable, supposable, surmisable -- (capable of being inferred on slight grounds)

Similarity of adj unthinkable

1 sense of unthinkable

Sense 1
unthinkable (vs. thinkable) -- (incapable of being conceived or considered)
       => impossible, inconceivable, out of the question, unimaginable -- (totally unlikely)
          Also See-> impossible#1; incredible#1, unbelievable#1