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

In the footage, Olivia tries to convince Jake to utilize the new twist to counteract a mole in an opposing alliance. —Sydney Bucksbaum, Entertainment Weekly, 25 Sep. 2025

The red counteracts the green, and the acidity helps neutralize the reaction. —Maureen Choi, Glamour, 25 Sep. 2025

The suggestion that a single medication could counteract the effects of autism is sure to be controversial, USA TODAY reported. —Diana Leyva, Nashville Tennessean, 25 Sep. 2025

The drug is typically prescribed to counteract the toxic effects of chemotherapy medications such as methotrexate and to treat anemia, and its effect on autism is still being debated. —Madeline Mitchell, USA Today, 24 Sep. 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