Antonyms of adj questionable

2 senses of questionable

Sense 1
questionable (vs. unquestionable) -- (subject to question; "questionable motives"; "a questionable reputation"; "a fire of questionable origin")

unquestionable (vs. questionable) -- (incapable of being questioned; "unquestionable authority")
        => acknowledged -- (generally accepted)
        => beyond doubt (predicate), indubitable -- (too obvious to be doubted)
        => for sure -- (not open to doubt; "she wanted to go; that was for sure")
        => mathematical -- (beyond question; "a mathematical certainty")
        => unimpeachable -- (beyond doubt or reproach; "an unimpeachable source")

Sense 2
questionable, refutable, confutable, confutative -- (able to be refuted)

INDIRECT (VIA deniable) -> undeniable -- (not possible to deny)

Similarity of adj questionable

2 senses of questionable

Sense 1
questionable (vs. unquestionable) -- (subject to question; "questionable motives"; "a questionable reputation"; "a fire of questionable origin")
       => alleged (prenominal), so-called, supposed -- (doubtful or suspect; "these so-called experts are no help")
       => apocryphal -- (being of questionable authenticity)
       => debatable, problematic, problematical -- (open to doubt or debate; "If you ever get married, which seems to be extremely problematic")
       => doubtful, dubious, dubitable, in question (predicate) -- (open to doubt or suspicion; "the candidate's doubtful past"; "he has a dubious record indeed"; "what one found uncertain the other found dubious or downright false"; "it was more than dubitable whether the friend was as influential as she thought"- Karen Horney)
       => equivocal -- (open to question; "aliens of equivocal loyalty"; "his conscience reproached him with the equivocal character of the union into which he had forced his son"-Anna Jameson)
       => fishy, funny, shady, suspect, suspicious -- (not as expected; "there was something fishy about the accident"; "up to some funny business"; "some definitely queer goings-on"; "a shady deal"; "her motives were suspect"; "suspicious behavior")
       => impugnable -- (subject to being discredited)
       => self-styled, soi-disant -- (as claimed by and for yourself often without justification; "the self-styled `doctor' has no degree of any kind")
          Also See-> contestable#1

Sense 2
questionable, refutable, confutable, confutative -- (able to be refuted)
       => deniable (vs. undeniable) -- (capable of being denied or contradicted)