Synonyms of questionable in English:

questionable


See definition of questionable

adjective

1‘it is questionable whether such an attack could be effective’

SYNONYMS
controversial, contentious, open to question, open to doubt, in doubt, doubtful, dubious, uncertain, unsure, debatable, in dispute, in question, arguable, problematic, problematical
unverified, unprovable, unresolved, unsettled, undecided, equivocal, unconvincing, implausible, improbable, not definite, unclear, not obvious, apocryphal, spurious, borderline, marginal, moot
informal iffy
British informal dodgy
ANTONYMS

certain, indisputable

2‘some of his questionable financial dealings have been investigated’

SYNONYMS
suspicious, suspect, under suspicion, irregular, dubious, doubtful, odd, queer, strange, not quite right, mysterious, murky, dark, shifty, unsavoury, disreputable, potentially dishonest, potentially illegal
informal funny, fishy, shady, iffy
British informal dodgy