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

Pair chin tucks with shoulder blade squeezes to counteract the forward hunch. — Hanna Wickes, Kansas City Star, 22 July 2026

Shoulder blade squeezes, pulling the shoulder blades together and holding for a few seconds, counteract the forward hunch that builds up during long screen sessions. — Hanna Wickes, Miami Herald, 22 July 2026

To counteract the supply shock, the International Energy Agency committed to drawing down global emergency inventories by a record 400 million barrels, creating a significant supply hole that will need to be filled. — David Goldman, CNN Money, 21 July 2026

The Cook County Department of Public Health is working to counteract vaccine misinformation, myths and confusion regarding vaccines as part of its efforts to increase vaccination rates. — Francine Knowles, Chicago Tribune, 20 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