fallacious

eristic (also eristical), misleading, sophistic (or sophistical), specious

half-baked, ill-advised, misguided, unconsidered, unreasoned

inconsistent

absurd, asinine, foolish, meaningless, nonsensical, preposterous, reasonless, senseless, silly

Kafkaesque, odd, peculiar, strange, surreal, unusual, weird

insane, mad, nutty, wacky (also whacky)

disordered, disorganized, rambling, random

unconvincing

inexplicable, unaccountable, unexplainable

artful, crafty, cunning, devious, foxy, guileful, shady, shifty, slick, sly, sneaking, sneaky, subtile, subtle, trick, trickish, tricky, underhand, underhanded, wily

inaccurate, incorrect, wrong

bewildering, confounding, distracting, perplexing, puzzling

ambidextrous, crooked, defrauding, dishonest, dissembling, double-dealing, duplicitous, faithless, fast, fraudulent, knavish, lying, mendacious, untrustworthy, untruthful

bogus, counterfeit, fake, feigned, forged, jive [slang], phony (also phoney), sham, spurious

insidious, perfidious, treacherous

ambiguous, circuitous, equivocal, evasive

artificial, backhanded, hypocritical, insincere, left-handed, two-faced