IPA: /ˌɪn.ækˈtɪv.eɪ.ʃən/
KK: /ɪnˈæktɪveɪʃən/
The process of making something not active or not working.
The inactivation of the virus was essential for the vaccine to be safe.
Inactivation → It is formed from "in-" (meaning not) and "activare" (meaning to make active) and the suffix "-tion" (indicating the action or process of). The word "inactivation" refers to the process of making something inactive or not active.
Think of 'not' ('in-') making something 'active' ('activare') — that's why inactivation means to make something inactive.