abstruse, arcane, beclouded, behind the curtain, behind the scenes, blind, buried, cabalistic, camouflaged, censored, classified, close, closed, clouded, covered, covert, cryptic, dark, disguised, eclipsed, enigmatic, esoteric, guarded, hermetic, hid, hidden, hush-hush, imperceptible, in a cloud, in a fog, in eclipse, in purdah, in the wings, incommunicado, indiscernible, insensible, invisible, latent, mysterious, obfuscated, obscure, obscured, occult, out of sight, privy, recondite, restricted, secluded, secluse, secret, sequestered, shrouded, sightless, smothered, stifled, submerged, suppressed, top secret, ulterior, unapparent, unbeheld, unbeholdable, unbreatheable, under an eclipse, under cover, under house arrest, under security, under wraps, underground, undiscernible, undisclosable, undisclosed, undivulgable, undivulged, unknown, unnoticed, unobserved, unperceivable, unperceived, unrealized, unrevealable, unrevealed, unseeable, unseen, unspoken, untellable, untold, unutterable, unuttered, unviewed, unwhisperable, unwitnessed, viewless, wrapped in clouds