neutralise in WordNet English dictionary

1. get rid of (someone who may be a threat) by killing
   "The mafia liquidated the informer"; "the double agent was neutralized"
   neutralize  neutralise  liquidate  waste  knock off  do in 
   
2. make ineffective by counterbalancing the effect of
   "Her optimism neutralizes his gloom"; "This action will negate the effect of my efforts"
   neutralize  neutralise  nullify  negate 
   
3. make chemically neutral
   "She neutralized the solution"
   neutralize  neutralise 
   
4. make incapable of military action
   neutralize  neutralise 
   

neutralise in English Wiktionary