Arcane

a.

1.

Hidden; secret.

Adj.

1.

arcane - requiring secret or mysterious knowledge; "the arcane science of dowsing"

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