verb

1. make chemically neutral

e.g. She neutralized the solution

Synonym: neutralise

2. make ineffective by counterbalancing the effect of

e.g. Her optimism neutralizes his gloom
This action will negate the effect of my efforts

Synonym: neutralisenullifynegate

3. make incapable of military action

Synonym: neutralise

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

e.g. The mafia liquidated the informer
the double agent was neutralized

Synonym: neutraliseliquidatewasteknock offdo in

5. make politically neutral and thus inoffensive

e.g. The treaty neutralized the small republic

6. oppose and mitigate the effects of by contrary actions

e.g. This will counteract the foolish actions of my colleagues

Synonym: counteractcountervailcounterbalance