Antonyms of adj unimpeachable

3 senses of unimpeachable

Sense 1
unimpeachable -- (beyond doubt or reproach; "an unimpeachable source")

INDIRECT (VIA unquestionable) -> questionable -- (subject to question; "questionable motives"; "a questionable reputation"; "a fire of questionable origin")

Sense 2
blameless, inculpable, irreproachable, unimpeachable -- (free of guilt; not subject to blame; "has lived a blameless life"; "of irreproachable character"; "an unimpeachable reputation")

INDIRECT (VIA innocent) -> guilty -- (responsible for or chargeable with a reprehensible act; "guilty of murder"; "the guilty person"; "secret guilty deeds")

Sense 3
unexceptionable, unimpeachable -- (completely acceptable; not open to exception or reproach; "two unexceptionable witnesses"; "a judge's ethics should be unexceptionable")

INDIRECT (VIA acceptable) -> unacceptable -- (not acceptable; not welcome; "a word unacceptable in polite society"; "an unacceptable violation of personal freedom")

Similarity of adj unimpeachable

3 senses of unimpeachable

Sense 1
unimpeachable -- (beyond doubt or reproach; "an unimpeachable source")
       => unquestionable (vs. questionable) -- (incapable of being questioned; "unquestionable authority")

Sense 2
blameless, inculpable, irreproachable, unimpeachable -- (free of guilt; not subject to blame; "has lived a blameless life"; "of irreproachable character"; "an unimpeachable reputation")
       => innocent (vs. guilty), guiltless, clean-handed -- (free from evil or guilt; "an innocent child"; "the principle that one is innocent until proved guilty")

Sense 3
unexceptionable, unimpeachable -- (completely acceptable; not open to exception or reproach; "two unexceptionable witnesses"; "a judge's ethics should be unexceptionable")
       => acceptable (vs. unacceptable) -- (worthy of acceptance or satisfactory; "acceptable levels of radiation"; "performances varied from acceptable to excellent")