Antonyms of adj thinkable

1 sense of thinkable

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

unthinkable (vs. thinkable) -- (incapable of being conceived or considered)
        => impossible, inconceivable, out of the question, unimaginable -- (totally unlikely)

Similarity of adj thinkable

1 sense of thinkable

Sense 1
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)
          Also See-> credible#1, believable#1; possible#1