1. [ verb ] act in opposition to
Synonyms: antagonise antagonize
Related terms: act antagonism
2. [ verb ] oppose and mitigate the effects of by contrary actions
Synonyms: neutralize counterbalance countervail

"This will counteract the foolish actions of my colleagues"

Related terms: cancel override counterbalance
3. [ verb ] oppose or check by a counteraction
Synonyms: countercheck
Related terms: control
4. [ verb ] destroy property or hinder normal operations
Synonyms: undermine subvert weaken countermine sabotage

"The Resistance sabotaged railroad operations during the war"

Related terms: disobey derail sabotage
Similar spelling:   counteractive