Synonyms of sly

1 Syllable

snook, smart, sharp, arch, mean, shark, shrewd, smooth, snuck, slick, wily

2 Syllables

bluffing, roguish, cunning, clever, devious, plotting, stealthiest, captious, covert, stealthier, thieving, slighty, sneakier, cagier, tricky, impish, dextrous, foxy, cannier, wary, cagey, wormed, foxier, sneaking, secret, stealthy, ribald, wilier, thievish, shifty, crafty, sneaky, canny, backstairs, shiftier, crooked, shrewdest, scheming, savvy, savvies, dodgy, subtle, shrewder, shiftiest, craftier, artful, warier, dickens, sneakiest

3 Syllables

retiary, deceitful, mischievous, streetwise, rascally, insidious, phoniness, conniving, furtive, dishonest, uncandid, ingenious, designing, underhand, astute, cleverest, treacherous, cleverer, vulpine, larcenous, plunderous, argute, intriguing, traitorous, dexterous, lubricious, two-faced, guileful, smooth-spoken, dissembling

4 Syllables

cloak-and-dagger, delusive, illusory, underhanded, elusive, ill-behaved, huggermugger, diplomatic, calculating, unscrupulous, deceptive, dirty-dealing, hole-and-corner, unprincipled, deviceful, evasive, insincere, surreptitious, double-dealing, machiavellian, disingenuous, unconscientious

5 Syllables

dishonorable, innovational, kleptomaniacal, under-the-table, exploitative

6 Syllables

prevaricatory, manipulative