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English definition of “sly”


adjective     /slaɪ/ (slyer, slyest)
deceiving people in a clever way to get what you want Sly and devious
sly smile a smile that shows you know something that other people do not: "I know why Chris didn't come home yesterday ," she said with a sly smile .Sly and devious
slyly adverb
(Definition of sly adjective from the Cambridge Learner's Dictionary © Cambridge University Press)

Definitions of “sly” in other dictionaries

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