neutralize
/ˈnuːtrəˌlaɪz/ /Brit ˈnjuːtrəˌlaɪz/
verb
also Brit neutralise -izes; -ized; -izing
[+ obj] to stop (someone or something) from being effective or harmful
technical :to cause (a chemical) to be neither an acid nor a base
to make (something, such as a country or area) neutral during a war