- cunning or wily: sly as a fox.
- stealthy, insidious, or secret.
- playfully artful, mischievous, or roguish: sly humor.
- on the sly, secretly; furtively: a tryst on the sly.
Origin of sly
SynonymsSee more synonyms for on Thesaurus.com
Examples from the Web for sly
Rambo movie marathon—11 am-12 am, AMCBecause nothing says the holidays like Sly Stallone and blood.The Ultimate Thanksgiving Weekend TV Guide: Must-See Marathons, Specials, and Parades
November 26, 2014
Her songs draw on Stevie Wonder, the Jackson 5, Sly Stone, Curtis Mayfield, and contemporary hip-hop.In the Backseat With Janelle Monae: A Limo Ride with the Stylish R&B Diva
April 28, 2014
Are its users loud and proud harbingers of the sex-tech revolution, or just people who want to get a bit freaky on the sly?Hook Up Apps Have Gone Too Far
March 7, 2014
In fact, some of us would like to think that Fallon meant it as a sly dig and knew exactly what he was asking.Can Jimmy Fallon Be Himself on ‘The Tonight Show’?
February 17, 2014
Her sly, skewering banter and provocative cynicism were her defense in a male-dominated profession and also her selling point.Tallulah Bankhead: Gay, Drunk and Liberated in an Era of Excess Art
January 25, 2014
"Let them sleep in the bed of honor," said the Princess Medea, with a sly smile at Jason.Tanglewood Tales
The sly, wicked Mimi came slinking to the place where the dragon lay.Opera Stories from Wagner
I know her sly manner of feeling her way with those gloves of hers.Little Dorrit
The faces seemed to have but one smile, conscious, sly, a little alarmed.The Coryston Family
Mrs. Humphry Ward
But I had only to open my lips to speak, and away she would run, with a sly smile.A Hero of Our Time
M. Y. Lermontov
- crafty; artfula sly dodge
- insidious; furtivea sly manner
- playfully mischievous; roguishsly humour
- on the sly in a secretive manner
Word Origin and History for sly
c.1200, "skillful, clever, dexterous," from Old Norse sloegr "cunning, crafty, sly," from Proto-Germanic *slogis (cf. Low German slu "cunning, sly," German schlau), probably from base *slak- "to strike, hit" (see slay (v.)), with an original notion of "able to hit." Cf. German verschlagen "cunning, crafty, sly," schlagfertig "quick-witted," literally "strike-ready," from schlagen "to strike." A non-pejorative use of the word lingered in northern English dialect until 20c. On the sly "in secret" is recorded from 1812. Sly-boots "a seeming Silly, but subtil Fellow" is in the 1700 "Dictionary of the Canting Crew."
Idioms and Phrases with sly
see on the sly.