Humean, Pyrrhonic, a bit thick, a bit thin, absurd, agnostic, ambitendent, ambivalent, amoral, arguable, at issue, at loose ends, beguiling, beyond belief, capricious, catchy, changeable, confutable, conjectural, conscienceless, contestable, controversial, controvertible, corrupt, corrupted, criminal, crooked, dark, debatable, deceiving, deceptive, delusive, delusory, deniable, devious, dishonest, dishonorable, disinclined, disputable, distrustful, double-minded, doubtable, doubtful, doubting, dubitable, equivocal, evasive, fallacious, false, felonious, fence-sitting, fence-straddling, fickle, fishy, fly-by-night, fraudulent, from Missouri, hallucinatory, hard of belief, hard to believe, hardly possible, hesitant, iffy, ill-got, ill-gotten, illusive, illusory, immoral, implausible, improbable, in dispute, in doubt, in dubio, in question, inconceivable, incredible, incredulous, indecisive, indirect, infirm of purpose, insecure, insidious, irresolute, irresolved, leery, mercurial, misleading, mistakable, mistrustful, mistrusting, moot, more than doubtful, mugwumpian, mugwumpish, mutable, not deserving belief, not kosher, of two minds, open, open to doubt, open to question, open to suspicion, passing belief, preposterous, problematic, questionable, questioning, refutable, reluctant, ridiculous, rocky, rotten, scrupulous, shady, shaky, shameless, shifty, shy, sinister, skeptic, skeptical, slippery, speculative, staggering belief, suppositional, suspect, suspecting, suspicious, tall, thick, thin, tottery, treacherous, trickish, tricksy, tricky, trustless, unbelievable, uncertain, unclear, unconscienced, unconscientious, unconscionable, unconvincing, undecided, undependable, underhand, underhanded, undetermined, unearthly, unethical, ungodly, unhealthy, unimaginable, unlikely, unpredictable, unprincipled, unpromising, unreliable, unresolved, unsafe, unsavory, unscrupulous, unsettled, unsound, unstable, unsteady, unstraightforward, unsure, unthinkable, untrusting, untrustworthy, untrusty, unworthy of belief, wary, without remorse, without shame