View synonyms for sly


[ slahy ]


comparative: slyer or slier [slahy, -er],superlative: slyest or sliest [slahy, -ist].
  1. cunning or wily:

    sly as a fox.

    Synonyms: astute, shrewd, crafty, foxy, subtle, artful

    Antonyms: obvious, direct

  2. stealthy, insidious, or secret.

    Synonyms: clandestine, underhand, furtive, surreptitious

  3. playfully artful, mischievous, or roguish:

    sly humor.


/ slaɪ /


  1. crafty; artful

    a sly dodge

  2. insidious; furtive

    a sly manner

  3. playfully mischievous; roguish

    sly humour


  1. on the sly
    in a secretive manner

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Derived Forms

  • ˈslyly, adverb
  • ˈslyness, noun

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Other Words From

  • slyly adverb
  • slyness noun
  • un·sly adjective unslyer unslyest
  • un·slyly adverb
  • un·slyness noun

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Word History and Origins

Origin of sly1

First recorded in 1150–1200; Middle English sly, sley , from Old Norse slœgr “sly, cunning” (originally “able to strike, able to slay”); slay ( def )

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Word History and Origins

Origin of sly1

C12: from Old Norse slǣgr clever, literally: able to strike, from slā to slay

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Idioms and Phrases

  1. on the sly, secretly;

    a tryst on the sly.

More idioms and phrases containing sly

see on the sly .

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Example Sentences

From a geeky standpoint, Smith’s reboot-y sequel series honors its predecessor in ways notable and sly, thereby allowing it to function both as an accessible entry point and as a fleshed-out extension of what came before.

It’s a show about fitness, but it’s also, in a sly way, about feminism.

On the subject of fashion, men have been quite the sly devils over the years.

Google security researchers are warning people to be on the lookout for a squad of sly hackers believed to be North Korean agents.

From Fortune

As Xu Bing himself has noted, his made-up characters “seem to upset intellectuals,” in a sly sendup of our respect for the written word.

Rambo movie marathon—11 am-12 am, AMCBecause nothing says the holidays like Sly Stallone and blood.

The movie has a very sly sense of humor, and I think people might miss that.

This weekend, you can see Sly lay waste to hundreds of fools in The Expendables 3.

Rylance was unforgettable as the mordantly sly king in Richard III, giving a brilliant new twist to a classic role.

Her songs draw on Stevie Wonder, the Jackson 5, Sly Stone, Curtis Mayfield, and contemporary hip-hop.

Jones said this with a chuckle and a sly expression in his face, as he glanced meaningly at his companion.

In the first place, one element of public-house talk—the overt or sly indecency—is left out.

He had known men who were almost as sly as rats; but on the whole he looked upon them as inferior beings.

There was a sly emphasis on the word, and a subtle humor in his look that showed the old detective at his worst.

We got Fanny a dress on the sly, gaudy black velvet and Duchesse lace.


Definitions and idiom definitions from 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.