• synonyms


See more synonyms for flex on Thesaurus.com
verb (used with object)
  1. to bend, as a part of the body: He flexed his arms to show off his muscles.
  2. to tighten (a muscle) by contraction.
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verb (used without object)
  1. to bend.
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  1. the act of flexing.
  2. British.
    1. any flexible, insulated electric cord; an electric cord or extension cord.
    2. Slang.an elastic band, as a garter.
  3. Mathematics. an inflection point.
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Origin of flex1

1515–25; (adj.) < Latin flexus, past participle of flectere to bend, turn; (noun) < Latin flexus act of bending, equivalent to flect(ere) + -tus suffix of v. action


  1. Informal. flexible: a flex program of workers' benefits.
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Origin of flex2

shortening of flexible


  1. a combining form representing flexible in compound words: flextime.
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Also flexi-.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words


Examples from the Web for flex

Contemporary Examples

Historical Examples

  • He picked it up and flexed it a bit, as a man might flex a rapier to test its material.

    Islands of Space

    John W Campbell

  • The function of this tendon is to flex the foot at the fetlock.

    Special Report on Diseases of the Horse

    United States Department of Agriculture

  • The Russians flex their 200-men muscles in an enclave in the Pristina airport.

    After the Rain

    Sam Vaknin

  • Her face was perfectly smooth, without a single hint of give or flex.

    Little Brother

    Cory Doctorow

  • When he was lying, he could flex the thigh and the legs slowly and feebly.

    Arteriosclerosis and Hypertension:

    Louis Marshall Warfield

British Dictionary definitions for flex


  1. British a flexible insulated electric cable, used esp to connect appliances to mainsUS and Canadian name: cord
  2. informal flexibility or pliability
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  1. to bend or be benthe flexed his arm; his arm flexed
  2. to contract (a muscle) or (of a muscle) to contract
  3. (intr) to work according to flexitime
  4. to test or display (one's authority or strength)
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Word Origin

C16: from Latin flexus bent, winding, from flectere to bend, bow
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 flex


1520s, probably a back-formation from flexible. Related: Flexed; flexing.

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Online Etymology Dictionary, © 2010 Douglas Harper

flex in Medicine


  1. To bend.
  2. To contract a muscle.
  3. To move a joint so that the parts it connects approach each other.
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.