1. (

• antagonize ,
• antagonise ,
• counteract

) act in opposition to ;

2. (

• countercheck ,
• counteract ,

) oppose or check by a counteraction ;

3. (

• counteract ,
• countervail ,
• neutralize ,
• counterbalance

) oppose and mitigate the effects of by contrary actions; "This will counteract the foolish actions of my colleagues" ;

4. (

• sabotage ,
• undermine ,
• countermine ,
• counteract ,
• subvert ,
• weaken

) destroy property or hinder normal operations; "The Resistance sabotaged railroad operations during the war" ;