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

While salicylic acid has a reputation for drying out skin, the triple ceramide complex in this cream counteracts that by drenching skin in long-lasting moisture—up to a full day—after application. — Mary Honkus, Glamour, 18 Aug. 2026

Warmer stretches throughout winter could actually melt additional snow with time, although consistent heavy snow would greatly counteract that melting. — Sean MacAday, Sacbee.com, 18 Aug. 2026

Authorities said equipment found at the ADU included hydraulic presses, cutting agents, personal protective equipment, scales and Narcan, a medication used to counteract the effects of opioids. — Jason Green, Mercury News, 18 Aug. 2026

Along with finding treatments for a host of other serious diseases, Fauci was instrumental in making strides to fight AIDS, Ebola, MERS, SARS, swine flu, and in developing drugs to counteract bioterrorism after 9/11. — Voice Of The People, New York Daily News, 15 Aug. 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