• synonyms


adjective, sly·er, sly·est.
  1. cunning or wily: sly as a fox.
  2. stealthy, insidious, or secret.
  3. playfully artful, mischievous, or roguish: sly humor.
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  1. on the sly, secretly; furtively: a tryst on the sly.
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Origin of sly

1150–1200; Middle English sly, sley, from Old Norse slœgr “sly, cunning” (originally “able to strike, able to slay”); see slay
Related formssly·ly, adverbsly·ness, nounun·sly, adjective, un·sly·er, un·sly·est.un·sly·ly, adverbun·sly·ness, noun

Synonyms for sly

Antonyms for sly

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for slyest

ingenious, intriguing, impish, shrewd, roguish, mischievous, canny, subtle, smart, arch, artful, astute, cagey, calculating, captious, covert, crafty, crooked, cunning, deceitful

Examples from the Web for slyest

Historical Examples of slyest

  • The coyote, or prairie-wolf, is the slyest animal that walks on four legs.

    The Boy Settlers

    Noah Brooks

  • It's the slyest trick the old fox has ever tried to play on us.

  • The mountain lion is one of the slyest and most elusive animals in the woods.

    Your National Parks

    Enos A. Mills

  • So they learned lots—and the slyest scoundrels learned the most.

  • When buckled down to his work he became the slyest and cleverest of diplomats.

    Parisians in the Country

    Honore de Balzac

British Dictionary definitions for slyest


adjective slyer, slyest, slier or sliest
  1. crafty; artfula sly dodge
  2. insidious; furtivea sly manner
  3. playfully mischievous; roguishsly humour
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  1. on the sly in a secretive manner
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Derived Formsslyly or slily, adverbslyness, noun

Word Origin for sly

C12: from Old Norse slǣgr clever, literally: able to strike, from slā to slay
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for slyest



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."

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Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with slyest


see on the sly.

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The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.