An example of something that would be described as sly is a devious secret plot to win an award.
A sly laugh.
Took a sly look at the letter on the table.
- In a way intended to escape notice:Took extra payments on the sly.
- secretly; stealthily
Origin of sly
- Middle English sleigh from Old Norse slœgr
From American Heritage Dictionary of the English Language, 5th Edition
- From Middle English sly, sley, from Old Norse slÇ£gr, slÅ“gr (“sly, cunning", literally “capable of hitting or striking"), from Proto-Germanic *slÅgiz (“lively, agile, cunning, sly, striking"), from Proto-Indo-European *slak- (“to hit, throw"). Cognate with Icelandic slÃ¦gur (“crafty, sly"), Norwegian Nynorsk slÃ¸g (“sly"), German schlau (“clever, crafty"). Related to sleight, slay.