counteract

verb

coun·​ter·​act ˌkau̇n-tər-ˈakt 

counteracted; counteracting; counteracts

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 

noun

counteractive

ˌkau̇n-tər-ˈak-tiv 

adjective

Synonyms of counteract

• offset
• neutralize
• correct

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

There’s also still work to be done to counteract soldiers’ longstanding preferences for fast food. — Kayla Hayempour, NBC news, 3 Aug. 2026

Propositions 41 and 42 — the two measures aimed at counteracting the billionaires tax — garnered an opposition position from the party. — Grace Hase, Mercury News, 3 Aug. 2026

These substances help counteract cell damage and inflammation that occur naturally from environmental factors and aging, Stefanski says. — Randi Gollin, Martha Stewart, 1 Aug. 2026

Additionally, doctors often recommend over-the-counter antihistamines such as Benadryl to counteract histamine released by the immune system. — Maggie O'Neill, Verywell Health, 29 July 2026

Word History

First Known Use

1655, in the meaning defined above

Rhymes for counteract

• artefact
• artifact
• inexact
• interact
• noncontact
• reenact
• subcontract
• abstract
• attacked
• attract
• contact
• contract

Kids Definition

counteract

verb

coun·​ter·​act ˌkau̇nt-ə-ˈrakt 

: to lessen the force, action, or influence of : offset

a drug that counteracts a poison

counteraction

-ˈrak-shən 

noun

Medical Definition

counteract

transitive verb

coun·​ter·​act ˌkau̇nt-ə-ˈrakt 

: 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 

noun