Breadcrumb Home > Dictionary > Index S sly: Meaning and Definition of Find definitions for: sly Pronunciation: (slī), [key] — adj., n. sly•er sli•er, sly•est sli•est, —adj. cunning or wily: sly as a fox. stealthy, insidious, or secret. playfully artful, mischievous, or roguish: sly humor. —n. secretly; furtively: a tryst on the sly. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: sly (Thesaurus) slutty slyboots TrendingHere are the facts and trivia that people are buzzing about. Who's Who in the "Lord of the Rings" Roman Catholic Church Hierarchy Current Events This Week: March 2023 42 Top Western Movie Quotes Slaves in the Family User's Guide to Environmental Language ✖ Related Content Daily Word Quiz: tangential Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language