1.make politically neutral and thus inoffensive;
The treaty neutralized the small republic
2.make ineffective by counterbalancing the effect of;
Her optimism neutralizes his gloom
3.oppose and mitigate the effects of by contrary actions;
This will counteract the foolish actions of my colleagues
4.get rid of (someone who may be a threat) by killing;
The mafia liquidated the informer
5.make incapable of military action
6.make chemically neutral;
She neutralized the solution