Justifying doubt
doubtful, dubious, uncertain, undefined, equivocal, disputable, arguable, obscure, inconclusive, controversial, vague, unsettled, open to doubt, indeterminate, debatable, moot, unconfirmed, problematic, cryptic, occult, apocryphal, hypothetical, mysterious, oracular, enigmatic, ambiguous, indefinite, contingent, provisional, paradoxical, under advisement, under examination, open to question, up for discussion, in question, to be voted on, to be decided, hard to believe, incredible, iffy*; see also uncertain 2.
Antonyms definite*, undoubted, certain.
Having a poor appearance or reputation
dubious, suspicious, suspect, disreputable, of doubtful character, irregular, notorious, of ill repute, unsatisfactory, unsound, thought ill of, under a cloud, unesteemed, ill-favored, unpopular, disagreeable, evil-looking, illegitimate, discreditable, disrespectable, unreliable, untrustworthy, dishonest, fly-by-night, shady*, fishy*, queer*; see also suspicious 2.
Antonyms honored*, esteemed, reputable. See syn. study at doubtful.doubtful.