sly
Americanadjective
comparative
slyer, slier,superlative
slyest, sliestidioms
adjective
-
crafty; artful
a sly dodge
-
insidious; furtive
a sly manner
-
playfully mischievous; roguish
sly humour
noun
Other Word Forms
- slyly adverb
- slyness noun
- unsly adjective
- unslyly adverb
- unslyness noun
Etymology
Origin of sly
First recorded in 1150–1200; Middle English sly, sley , from Old Norse slœgr “sly, cunning” (originally “able to strike, able to slay”); slay ( def. )
Explanation
When you're sly, you're crafty, cunning, tricky, and wily. Being sly is being deceitful, though not in the worst way. If you're good at lying, you're quite sly: people who are sly are good at pulling one over on other people. Being sly helps you get away with things. If you made a mess in your house but got your parents to blame the dog, that was sly. Being sly means you're not being honest, but this word has kind of a harmless flavor to it. Someone who killed someone and lied about it would not be described as sly. Slyness has to do with smaller, sneakier, more harmless kinds of lying.
Vocabulary lists containing sly
"The Yellow Wallpaper" by Charlotte Perkins Gilman
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Charlie and the Chocolate Factory
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Scrabble: Words with no Vowels
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
She has a sly way of imparting lessons, often with playfulness.
From Los Angeles Times • Jan. 14, 2026
"Nobody had agreed to it at all. Really sly," fellow chorister Kevin Doughty says in Con Jones: World's Best Conman.
From BBC • Dec. 31, 2025
Here, it is a man whose labor disappears behind a woman’s byline, a sly inversion of the far more familiar historical pattern.
From Salon • Dec. 25, 2025
The math-proficiency analysis suggests it may be doing so on the sly.
From The Wall Street Journal • Nov. 30, 2025
Much of the laughter had to do with her father’s sly wit and sharp tongue.
From "The Birchbark House" by Louise Erdrich
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
