quacksalver

abstruse, esoteric, recondite

cloaked, concealed, disguised, masked, shrouded

beclouded, bedimmed, befogged, clouded, cloudy, dim, faint, foggy, fuzzy, hazy, indistinct, indistinguishable, misty, muddy, obfuscatory, obnubilated, obscurant (or obscurantic), shaded, shadowlike, shadowy, sphinxlike

indefinite, inexact, inexplicit, noncommittal, questionable, unclear, uncertain, undefined, undetermined, vague

impenetrable, incomprehensible, indecipherable, inexplicable

eerie (also eery), uncanny, weird

impalpable, inappreciable, intangible, invisible

unanswerable, unknowable

baffling, bewildering, confounding, confusing, mystifying, perplexing, puzzling, unfathomable

circuitous, indirect, roundabout

complex, complicated, difficult, obtuse

comprehensible, fathomable, intelligible, knowable, legible, pellucid, understandable

bright, distinct, evident, self-evident, self-explanatory

certain, firm, strong, sure

defined, determined

direct, straightforward

definite, exact, explicit

appreciable, palpable, tangible, visible

blatant, patent, unmistakable

accessible, clear, nonambiguous, obvious, plain, unambiguous, unequivocal