SLY, CUNNING, CRAFTY, WILY, TRICKY, FOXY, ARTFUL, SLICK mean attaining or seeking to attain one's ends by guileful or devious means.

SLY implies furtiveness, lack of candor, and skill in concealing one's aims and methods.

e.g. a sly corporate raider

CUNNING suggests the inventive use of sometimes limited intelligence in overreaching or circumventing.

e.g. the cunning fox avoided the trap

CRAFTY implies cleverness and subtlety of method.

e.g. a crafty lefthander

WILY implies skill and deception in maneuvering.

e.g. the wily fugitive escaped the posse

TRICKY is more likely to suggest shiftiness and unreliability than skill in deception and maneuvering.

e.g. a tricky political operative

FOXY implies a shrewd and wary craftiness usually involving devious dealing.

e.g. a foxy publicity man planting stories

ARTFUL implies indirectness in dealing and often connotes sophistication or cleverness.

e.g. elicited the information by artful questioning

SLICK emphasizes smoothness and guile.

e.g. slick operators selling time-sharing

adjective (slyer, slyest)

having or showing a cunning and deceitful nature:

ずるい, あくどい, こすい

e.g. she had a sly personality.

(of a remark, glance, or facial expression) showing in an insinuating way that one has some secret knowledge that may be harmful or embarrassing:

〈ユーモアなどが〉茶目っ気のある, いたずらっぽい.

e.g. he gave a sly grin.

(of an action) surreptitious:

〖通例名詞の前で〗こそこそした, 陰険な〈目つきなど〉

e.g. a sly sip of water.

in a secretive fashion:

e.g. she was drinking on the sly.

slyness |ˈslīnəs| noun

Middle English (also in the sense ‘dexterous’): from Old Norse slœgr ‘cunning’, originally ‘able to strike’ from the verb slá; compare with sleight.