secret

1 undertaken or done so as to escape being observed or known by others a secret operation to rescue captive soldiers behind enemy lines Synonyms backstairs, behind-the-scenes, clandestine, covert, furtive, hole-and-corner, hugger-mugger, hush-hush, private, privy, sneak, sneaking, sneaky, stealth, stealthy, surreptitious, undercover, underground, underhand, underhanded Related Words back-channel, closed-door, off-the-books, off-the-record; classified, confidential, restricted, top secret, undisclosed; concealed, hidden, secreted, subterranean, unadvertised, unexposed Near Antonyms acknowledged, avowed; aboveboard, straightforward, unconcealed, undisguised; unclassified, unrestricted; clear, evident, manifest, obvious, patent, plain Antonyms open, overt, public

2 working on missions in which one's objectives, activities, or true identity are not publicly revealed secret agents whose wartime exploits were known only by top government officials Synonyms undercover Related Words covert, private, secretive, subterranean Near Antonyms overt

3 screened or sequestered from view a secret cave that is screened by trees Synonyms cloistered, covert, hidden, isolated, quiet, remote, retired, secluded, shelteredRelated Words lone, lonely, lonesome, reclusive, solitary; privateNear Antonyms obvious, visible; exposed

4 not known or meant to be known by the general populace proprietary information that the company does its best to keep secret Synonyms behind-the-scenes, confidential, esoteric, hushed, hush-hush, inside, intimate, nonpublic, privy, privateRelated Words classified, restricted, top secret; silent, unadvertised, unannounced, undisclosed, unmentioned, unsaid, untold; clandestine, closet, collusive, conspiratorial, covert; furtive, hugger-mugger, occult, sneak, sneaking, sneaky, stealthy, surreptitious, undercover, underground, underhand, underhanded; personal; closeted, concealed, hidden; repressed, silenced, stifled, suppressed; backstage, offscreen, offstageNear Antonyms well-known; advertised, aired, announced, blazed, broadcast, declared, disclosed, divulged, enunciated, heralded, proclaimed, professed, promulgated, publicized, published, reported, spotlighted; general, popular, prevailing, vulgar; current, prevalent, rife, widespread; communal, sharedAntonyms common, open, public