First Known Use: 13th century
Dictionary
sly
adjective \ˈslī\
: clever in a dishonest way
: showing that you know a secret
sli·er or sly·er \ˈslī(-ə)r\ sli·est or sly·est \ˈslī-əst\
Full Definition of SLY
1
2
a : clever in concealing one's aims or ends : furtive b : lacking in straightforwardness and candor : dissembling
3
: lightly mischievous : roguish <a sly jest>
— sly·ly also sli·ly adverb
— sly·ness noun
— on the sly
: in a manner intended to avoid notice
See sly defined for English-language learners
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Origin of SLY
Middle English sleighe, sli, from Old Norse slœgr; akin to Old English slēan to strike — more at slay
Related to SLY
Synonym Discussion of SLY
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 <a sly corporate raider>. cunning suggests the inventive use of sometimes limited intelligence in overreaching or circumventing <the cunning fox avoided the trap>. crafty implies cleverness and subtlety of method <a crafty lefthander>. wily implies skill and deception in maneuvering <the wily fugitive escaped the posse>. tricky is more likely to suggest shiftiness and unreliability than skill in deception and maneuvering <a tricky political operative>. foxy implies a shrewd and wary craftiness usually involving devious dealing <a foxy publicity man planting stories>. artful implies indirectness in dealing and often connotes sophistication or cleverness <elicited the information by artful questioning>. slick emphasizes smoothness and guile <slick operators selling time-sharing>.
SLYNESS Defined for Kids
sly
adjective \ˈslī\
sli·er or sly·ersli·est or sly·est
Definition of SLY for Kids
1
: both clever and tricky
2
: tending to keep secrets and hide intentions
3
: mischievous 2 <There were teachers all over the place, and any kind of fighting or taunting, above a sly pinch … was out. — Lynne Reid Banks, The Indian in the Cupboard>
— sly·ly adverb
— sly·ness noun
— on the sly
: so as not to be seen or caught : secretly
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