Humean, Pyrrhonic, agnostic, ambiguous, capricious, cautious, chancy, changeable, cynical, dicey, disbelieving, disinclined to believe, disposed to doubt, dissenting, distrustful, doubtful, doubting, dubious, equivocal, erratic, fickle, freethinking, from Missouri, guarded, hard of belief, hesitant, hesitating, impervious to persuasion, in doubt, incalculable, inconvincible, incredulous, indecisive, indemonstrable, irresolute, leery, mistrustful, mistrusting, polysemous, questioning, scrupulous, shy, shy of belief, skeptic, suspecting, suspicious, touch-and-go, unaccountable, unbelieving, uncertain, unconfirmable, unconvinced, unconvincible, uncredulous, undivinable, unforeseeable, unpersuadable, unpersuaded, unpersuasible, unpredictable, unprovable, unsure, untrusting, unverifiable, unwilling to accept, variable, wary, wavering, whimsical