questionable
I
(dubious) adjective
ambiguous, arguable, at issue, contestable, controversial, controvertible, debatable, disputable, doubtable, doubtful, dubious, dubitable, enigmatical, equivocal, experimental, fallible, hard to believe, hardly possible, improbable, inconceivable, incredible, indefinite, indeterminate, in dispute, in question, moot, more than doubtful, not axiomatic, objectionable, open to doubt, open to question, perplexing, puzzling, speculative, suspect, suspicious, tentative, unauthentic, uncertain, unconvincing, undecided, undetermined, unlikely, unreliable, unsettled, unsound, unsure, unsustainable, untenable, untrustworthy, vague
II
(unethical) adjective
corrupt, dishonest, dishonorable, disreputable, ill-gotten, immoral, perfidious, shady, unconscionable, underhanded, unprincipled, unscrupulous, untrustworthy
III
index
blameworthy, contestable, controversial, debatable, disputable, doubtful, dubious, dubitative, equivocal, implausible, indefinite, lewd, ludicrous, moot, outrageous, problematic, speculative, tentative, unbelievable, undecided, unethical, unscrupulous, unsound (fallacious), unsustainable, untenable, untrustworthy, vague
Burton's Legal Thesaurus.
William C. Burton.
2006