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

Here are some of the costs — and how to counteract them. —Tessa West, CNBC, 13 Apr. 2026

Alongside these minerals, dark chocolate is rich in antioxidants, which help counteract free radicals—harmful molecules linked to chronic diseases. —Lana Barhum, Verywell Health, 13 Apr. 2026

By applying lower‑body compression, the garment helps counteract a common condition called orthostatic intolerance that causes astronauts to faint or feel dizzy following an extended mission in microgravity. —Eric Lagatta, USA Today, 9 Apr. 2026

This force pushes outward, counteracting the inward pull of gravity. —Rupendra Brahambhatt, Interesting Engineering, 4 Apr. 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