doubtful

1 not feeling sure about the truth, wisdom, or trustworthiness of someone or something <he was doubtful about the decision to complete the project despite its mounting problems> Synonyms distrustful, dubious, hinky [slang], mistrustful, skeptical, suspicious, trustless, uncertain, unconvinced, undecided, unsettled, unsure Related Words ambivalent, conflicted, equivocal; diffident, insecure; halting, hesitant, indecisive, irresolute, vacillating, wavering Phrases on the fence Near Antonyms assured, confident, sanguine, self-assured; decisive, determined, resolute Antonyms certain, convinced, positive, sure

2 giving good reason for being doubted, questioned, or challenged <the election results were highly doubtful, so an investigation was begun> Synonyms debatable, disputable, dodgy [chiefly British], doubtable, dubious, dubitable, equivocal, fishy, problematic (also problematical), queer, questionable, shady, shaky, suspect, suspicious Related Words alleged, so-called, supposed; moot; ambiguous, open, unclear; uncertain, undecided, undetermined; far-fetched, flimsy, improbable, unlikely, weak Near Antonyms decisive, definitive; clear, obvious, open-and-shut, positive Antonyms certain, hands-down, incontestable, indisputable, indubitable, questionless, sure, undeniable, undoubted, unproblematic, unquestionable

3 not likely to be true or to occur <our winning the championship increasingly looks like a doubtful outcome> Synonyms improbable, dubious, far-fetched, flimsy, questionable, unapt, unlikelyRelated Words implausible, impossible, inconceivable, incredible, unbelievable, unimaginable, unthinkable; absurd, bizarre, crazy, fantastic (also fantastical), foolish, insane, nonsensical, odd, outlandish, preposterous, ridiculous, unreal, wild; outside, remote, slightNear Antonyms believable, conceivable, credible, earthly, imaginable, plausible; possible, potential; liableAntonyms likely, probable

4 open to question or dispute <a doubtful claim to the property> Synonyms arguable, controvertible, disputable, doubtable, debatable, issuable, moot, negotiable, questionableRelated Words contradictable, refutable; controversial, debated, disputed; dubious, iffy, inconclusive, indecisive, problematic (also problematical), shaky, uncertain; academic (also academical), hypothetical, speculative, theoretical (also theoretic); ambiguous, equivocalNear Antonyms irrefutable; definite; unambiguous, unequivocal; absolute, clear, conclusive, decisive; uncontested, undisputedAntonyms accomplished, certain, hands-down, inarguable, incontestable, incontrovertible, indisputable, indubitable, irrefragable, positive, questionless, settled, sure, unanswerable, unarguable, unchallengeable, undebatable, undeniable, unquestionable