counteract

verb

coun·​ter·​act ˌkau̇n-tər-ˈakt How to pronounce counteract (audio)
counteracted; counteracting; counteracts
Synonyms of counteractnext

transitive verb

: to make ineffective or restrain or neutralize the usually ill effects of by means of an opposite force, action, or influence
a drug used to counteract fatigue
counteraction
ˌkau̇n-tər-ˈak-shən How to pronounce counteract (audio)
noun
counteractive
ˌkau̇n-tər-ˈak-tiv How to pronounce counteract (audio)
adjective

Synonyms of counteract

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Examples of counteract in a Sentence

The drug will counteract the poison. this medication will counteract the symptoms but it won't kill the infection
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The emergence of Chase Burns in 2026 has been counteracted by a lost season for Hunter Greene and the collective struggles of Andrew Abbott, Nick Lodolo and Rhett Lowder. — Andy McCullough, New York Times, 3 Sep. 2026 Unlike some spacecraft in low Earth orbit, Swift doesn't have a propulsion system capable of counteracting atmospheric drag. — Samantha Mathewson, Space.com, 31 Aug. 2026 Sea salt gives hair that tousled texture, while red microalgae extract helps counteract the drying effects of salt. — Christa Joanna Lee, Allure, 28 Aug. 2026 Ferroni said that's likely because the weight of active capital in the market is counteracting and potentially working as a stronger force than that ongoing volatility. — Diana Olick, CNBC, 25 Aug. 2026 See All Example Sentences for counteract

Word History

First Known Use

1655, in the meaning defined above

Time Traveler
The first known use of counteract was in 1655

Rhymes for counteract

See All Rhymes for counteract

Browse Nearby Words

counteraccusation
counteract
counteractant
See all Nearby Words

Cite this Entry

“Counteract.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/counteract. Accessed 4 Sep. 2026.

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Kids Definition

counteract

verb
coun·​ter·​act ˌkau̇nt-ə-ˈrakt How to pronounce counteract (audio)
: to lessen the force, action, or influence of : offset
a drug that counteracts a poison
counteraction
-ˈrak-shən How to pronounce counteract (audio)
noun

Medical Definition

counteract

transitive verb
coun·​ter·​act ˌkau̇nt-ə-ˈrakt How to pronounce counteract (audio)
: to make ineffective or restrain or neutralize the usually ill effects of by an opposite force
vitamin K counteracts the effects of warfarin
counteraction
-ˈrak-shən How to pronounce counteract (audio)
noun
Last Updated: - Updated example sentences
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