doubtful

doubtful, dubious, problematic, questionable mean not affording assurance of the worth, soundness, or certainty of something. doubtful implies little more than a lack of conviction or certainty <doubtful about whether I said the right thing>. dubious stresses suspicion, mistrust, or hesitation <dubious about the practicality of the scheme>. problematic applies especially to things whose existence, meaning, fulfillment, or realization is highly uncertain <whether the project will ever be finished is problematic>. questionable may imply no more than the existence of doubt but usually suggests that the suspicions are well-grounded <a man of questionable honesty>.