sly
Americanadjective
idioms
adjective
-
crafty; artful
a sly dodge
-
insidious; furtive
a sly manner
-
playfully mischievous; roguish
sly humour
noun
Other Word Forms
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”); see 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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Charlie and the Chocolate Factory
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
Scrabble: Words with no Vowels
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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.
I saw his pale skin turned purple, his sly mouth gone flat.
From Slate • Apr. 23, 2026
After he saves the day, and his Daily Planet colleagues remark on Superman’s skills, his alter ego Clark Kent gives a sly glance to the camera, letting the audience in on the, quite obvious, ruse.
From The Wall Street Journal • Feb. 7, 2026
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
“Already waiting back in the city,” Rio said with a sly grin.
From "City Spies" by James Ponti
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.
