neutralise

(verb) get rid of (someone who may be a threat) by killing. Synonyms: neutralize, liquidate, waste, knock off, do in. Examples: "The mafia liquidated the informer." "The double agent was neutralized."

(verb) make incapable of military action. Synonyms: neutralize.

(verb) make ineffective by counterbalancing the effect of. Synonyms: neutralize, nullify, negate. Examples: "Her optimism neutralizes his gloom." "This action will negate the effect of my efforts."

(verb) make chemically neutral. Synonyms: neutralize. Example: "She neutralized the solution."