adj. 25B6; adjective
jokes of questionable taste : CONTROVERSIAL, contentious, doubtful, dubious, uncertain, debatable, arguable; unverified, unprovable, unresolved, unconvincing, implausible, improbable; borderline, marginal, moot; informal iffy; Brit. informal dodgy.
questionable financial dealings : SUSPICIOUS, suspect, dubious, irregular, odd, strange, murky, dark, unsavoury, disreputable; informal funny, fishy, shady, iffy; Brit. informal dodgy.
indisputable, honest.