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

• 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

Antioxidants are substances that may help counteract the effects of free radicals in the body.6 Free radicals are highly reactive substances that can damage cellular structures and DNA, potentially contributing to the development of chronic conditions and other health issues. —Lana Barhum, Verywell Health, 23 July 2025

But your biology isn’t entirely your destiny, Dr. Schoenfeld said, and strength training can go a long way toward slowing or counteracting these changes. —New York Times, 22 July 2025

To counteract this unintentional sabotage, start by cleaning your gutters. —Hallie Milstein, Southern Living, 17 July 2025

Governments face challenges to counteract digital deception and maintain democratic integrity. —Ivan Shkvarun, Forbes.com, 9 July 2025

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