The meaning of SLY is wise in practical affairs. How to use sly in a sentence. Synonym Discussion of Sly.
The meaning "insidious, crafty, meanly artful" is from c. 1200. That of "playfully artful, knowing" is from 1764. In Middle Englishsly wordscould mean "wise words" or "deceptive language." A non-pejorative use of the word lingered in northern English dialect until 20c.On the sly"in sec...