neutralize

make politically neutral and thus inoffensive

• “The treaty neutralized the small republic”

make ineffective by counterbalancing the effect of

• “Her optimism neutralizes his gloom”
• “This action will negate the effect of my efforts”

oppose and mitigate the effects of by contrary actions

• “This will counteract the foolish actions of my colleagues”

get rid of (someone who may be a threat) by killing

• “The mafia liquidated the informer”
• “the double agent was neutralized”

make incapable of military action

make chemically neutral

• “She neutralized the solution”