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counteract

[koun-ter-akt]
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verb (used with object)
  1. to act in opposition to; frustrate by contrary action.
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Origin of counteract

First recorded in 1670–80; counter- + act
Related formscoun·ter·ac·tant, adjectivecoun·ter·act·er, coun·ter·ac·tor, nouncoun·ter·act·ing·ly, adverbcoun·ter·ac·tion, nouncoun·ter·ac·tive, adjectivecoun·ter·ac·tive·ly, adverbnon·coun·ter·ac·tive, adjectiveun·coun·ter·act·ed, adjective

Synonyms

See more synonyms for counteract on Thesaurus.com
neutralize, counterbalance, contravene, thwart.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for counteractant

Historical Examples

  • What had Clay to offer as a counteractant, as an equal inspiration to the pride of this lusty nation?

    Children of the Market Place

    Edgar Lee Masters


British Dictionary definitions for counteractant

counteract

verb
  1. (tr) to oppose, neutralize, or mitigate the effects of by contrary action; check
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Derived Formscounteraction, nouncounteractive, adjectivecounteractively, adverb
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 counteractant

counteract

v.

1670s, from counter- + act (v.). Related: Counteracted; counteracting.

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Online Etymology Dictionary, © 2010 Douglas Harper