The definition of sly is someone or something that is clever in a deceitful or cunning way.(adjective)
An example of something that would be described as sly is a devious secret plot to win an award.
See sly in Webster's New World College Dictionary
Origin: ME sley < ON slœgr, clever, cunning, lit., able to strike < base of slā & OE slean, to strike: see slay
See sly in American Heritage Dictionary 4
adjective sli·er (slīˈər) also sly·er, sli·est (slīˈĕst) also sly·est
Origin: Middle English sleigh
Origin: , from Old Norse slœgr.
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