furtive

1 given to acting in secret and to concealing one's intentions a furtive guy who always seems to be up to something, and usually that something is no-good Synonyms sneaky, shady, shifty, slippery, sly, sneaking, stealthyRelated 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, treacherousNear 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 gave each other furtive glances as we watched our friend open the booby-trapped soda Synonyms backstairs, behind-the-scenes, clandestine, covert, secret, hole-and-corner, hugger-mugger, hush-hush, private, privy, sneak, sneaking, sneaky, 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