(a.) Of or pertaining to mystery; containing a mystery; difficult or impossible to understand; obscure not revealed or explained; enigmatical; incomprehensible.

able abstruse ambiguous amphibological amphibolous anagogic arcane awe-inspiring awesome awful awing baffling beclouded bewildering bizarre blind bothering buried cabalic cabalistic censored classified close closed clouded concealed confounding confusing covered covert cryptic curious dark discomposing disconcerting dismaying distracting disturbing eclipsed eerie embarrassing enigmatic enwrapped in mystery equivocal equivocatory esoteric extramundane extraterrestrial fey furtive hermetic hid hidden hush-hush hypernormal hyperphysical impenetrable in a cloud in a fog in eclipse in purdah in the wings incalculable incognizable incommunicado incomprehensible indefinable inexplicable inextricable inscrutable insoluble insolvable intricate ironic latent metaphysic multivocal mystic mystical mystifying numinous obfuscated obscure obscured occult otherworldly perplexing perturbing polysemantic polysemous preterhuman preternatural preternormal pretersensual problematic psychic puzzling recondite restricted sealed secluded secluse secret sequestered smothered spiritual stifled strange superhuman supernatural supernormal superphysical supersensible supersensual suppressed supramundane supranatural theosophical theosophist top secret transcendental transmundane ulterior unaccountable unapparent unapprehended unascertained unbeknown unbreatheable uncanny uncertain uncharted unclassified unclear undefinable under an eclipse under cover under house arrest under security under wraps underground undisclosable undisclosed undiscoverable undiscovered undivulgable undivulged unearthly unexplainable unexplained unexplored unexposed unfamiliar unfathomable unfathomed ungraspable unguessed unheard unheard-of unhuman unidentified unintelligible uninterpretable uninvestigated unknowable unknown unperceived unplumbed unrevealable unrevealed unsolvable unspoken unsuspected untellable untold untouched unutterable unuttered unwhisperable unworldly upsetting virgin weird wrapped in clouds