(a.) Beyond the reach of the senses; above the natural powers of perception.

abstract abstruse cabalistic censored classified close closed concealed cryptic dark deep eerie enigmatic esoteric extramundane extraterrestrial fey hermetic hidden hush-hush hypernormal hyperphysical impenetrable inscrutable latent mysterious mystic mystical numinous occult otherworldly preterhuman preternatural preternormal pretersensual profound psychic recondite restricted secret smothered spiritual stifled superhuman supernatural supernormal superphysical supersensible supersensual suppressed supramundane supranatural top secret transcendental transmundane ulterior unaccountable unbreatheable uncanny under security under wraps undisclosable undisclosed undivulgable undivulged unearthly unguessed unhuman unknowable unrevealable unrevealed unspoken untellable untold unutterable unuttered unwhisperable unworldly weird