Privy

Adjective

 * 1)  Private, exclusive; that is one's own.
 * The king retreated to his privy chamber.
 * 1)  Secret, hidden, concealed.
 * 2) With knowledge of; party to; let in on.
 * He was privy to the discussions.

Noun

 * 1) an outdoor toilet; latrine; earth closet; john; johnny house.

Thesaurus
WC, alive to, anonymous, appreciative of, apprised of, awake to, aware of, back-door, backhouse, backstairs, basement, bathroom, behind the curtain, behind the scenes, bog, buried, can, clandestine, closet, cognizant of, comfort station, concealed, conscious of, convenience, covert, crapper, earth closet, feline, furtive, head, hep to, hidden, hidlings, hole-and-corner, hugger-mugger, in the know, in the secret, incognito, informed of, inmost, innermost, interior, intimate, inward, isolated, jakes, john, johnny, johnny house, latrine, lavatory, let into, loo, mindful of, necessary, no stranger to, obscured, office, on to, outhouse, personal, powder room, private, privileged, privy to, quiet, rest room, retired, secluded, secret, seized of, sensible of, sensible to, sequestered, shifty, shrouded, skulking, slinking, slinky, sly, sneaking, sneaky, stealthy, streetwise, surreptitious, toilet, toilet room, undeceived, under-the-counter, under-the-table, undercover, underground, underhand, underhanded, unobtrusive, urinal, washroom, water closet, wise to, withdrawn