deactivate Syllabification: (de·ac·ti·vate)Pronunciation: /dēˈaktəvāt/Definition of deactivate verb [with object] make (something, typically technical equipment or a virus) inactive by disconnecting or destroying it:the switch deactivates the alarm Military remove from active duty. Derivatives deactivationPronunciation: /dēˌaktəˈvāSHən/ noun deactivatorPronunciation: /-vātər/ noun deactivate in other Oxford dictionaries Definition of deactivate in the British & World English dictionary