sneaky

1 given to acting in secret and to concealing one's intentions his opponent's sneaky campaign manager was clearly up to something Synonyms furtive, shady, shifty, slippery, sly, sneaking, stealthy Related Words artful, crafty, cunning, devious, foxy, guileful, slick, wily; close, closemouthed, reticent, secretive; clandestine, covert, dark; deceitful, deceiving, deceptive, devious, duplicitous, trickish, tricky, underhand, underhanded; cheating, crooked, defrauding, dishonest, dissembling, double-dealing, knavish, two-faced; lying, mendacious, untrustworthy, untruthful; insidious, perfidious, serpentine, treacherous Near Antonyms aboveboard, forthright, plainspoken, straightforward; candid, direct, foursquare, frank, open, plain; honest, trustworthy, truthful

2 undertaken or done so as to escape being observed or known by others a sneaky plan to replace the priceless painting with a copy Synonyms backstairs, behind-the-scenes, clandestine, covert, furtive, hole-and-corner, hugger-mugger, hush-hush, private, privy, sneak, sneaking, secret, stealth, stealthy, surreptitious, undercover, underground, underhand, underhandedRelated Words back-channel, closed-door, off-the-books, off-the-record; classified, confidential, restricted, top secret, undisclosed; concealed, hidden, secreted, subterranean, unadvertised, unexposedNear Antonyms acknowledged, avowed; aboveboard, straightforward, unconcealed, undisguised; unclassified, unrestricted; clear, evident, manifest, obvious, patent, plainAntonyms open, overt, public