Dictionary.com
Thesaurus.com
Synonyms

counteract

American  
[koun-ter-akt] / ˌkaʊn tərˈækt /

verb (used with object)

  1. to act in opposition to; frustrate by contrary action.

    Synonyms:
    thwart, contravene, counterbalance, neutralize

counteract British  
/ ˌkaʊntərˈækt /

verb

  1. (tr) to oppose, neutralize, or mitigate the effects of by contrary action; check

"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

Other Word Forms

  • counteractant adjective
  • counteracter noun
  • counteractingly adverb
  • counteraction noun
  • counteractive adjective
  • counteractively adverb
  • counteractor noun
  • noncounteractive adjective
  • uncounteracted adjective

Etymology

Origin of counteract

First recorded in 1670–80; counter- + act

Explanation

To counteract is to work against something in an attempt to reverse it or cancel it out. You can try to counteract the neighbors' annoyance at your loud music by bringing them some homemade brownies. When you counteract something, you act counter — or in opposition — to it. To counteract rising global temperatures, we have to reduce the greenhouse gases flowing into the atmosphere. In order to counteract the effects of a long sleepless night, you may want to drink a cup of coffee or tea. And a good way to counteract a limited vocabulary is to learn a new word every day!

Keep Reading on Vocabulary.com

Vocabulary lists containing counteract

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.

None of it did much to counteract the sense that life had become too expensive.

From Slate • Mar. 25, 2026

Announcing its approval, the FCC said the deal would help "counteract the growing imbalance of power" between local broadcast TV stations and the large media firms, including Fox, Disney and Paramount, that dominate programming.

From BBC • Mar. 20, 2026

The researchers evaluated whether WUSTL0717 could counteract the severe weight loss that often follows small bowel resection.

From Science Daily • Mar. 18, 2026

Former Manchester City goalkeeper Shay Given suggested earlier this season that keeping players up while defending corners could be an effective way to counteract Arsenal's threat.

From BBC • Mar. 11, 2026

Sensing the problem, the ascent software angled the ship into the wind to counteract it.

From "The Martian" by Andy Weir