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

Satellites perform a delicate dance to maintain their orbit, by locking themselves to a speed just fast enough to counteract the downward pull of gravity. — Victor Tangermann, Futurism, 9 July 2026

This ambitious strategy, known as marine cloud brightening (MCB), has been one of several geoengineering strategies contemplated as a way to counteract global warming. — Cody Cottier, Scientific American, 8 July 2026

This powder room in a Vermont Schoolhouse is drenched with Farrow & Ball’s Eating Room Red, a color that actually expands the tight space, while this Manhattan loft employs all-pink cabinets to counteract cold granite. — Julia Harrison, Architectural Digest, 7 July 2026

These physiological adaptations may play a role in counteracting cardiovascular risk factors, according to the authors of the study published June 17 in the Journal of the American College of Cardiology. — Dana Santas, CNN Money, 7 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