Antonyms of adj assertable

1 sense of assertable

Sense 1
affirmable, assertable -- (capable of being affirmed or asserted; "a quality affirmable of every member of the family")

INDIRECT (VIA possible) -> impossible -- (not capable of occurring or being accomplished or dealt with; "an impossible dream"; "an impossible situation")

Similarity of adj assertable

1 sense of assertable

Sense 1
affirmable, assertable -- (capable of being affirmed or asserted; "a quality affirmable of every member of the family")
       => possible (vs. impossible) -- (capable of happening or existing; "a breakthrough may be possible next year"; "anything is possible"; "warned of possible consequences")