deactivation vs firing

deactivation and firing both are nouns.

Word	Noun	Adjective	Verb	Adverb
deactivation	Yes	No	No	No
firing	Yes	No	No	No

As nouns, firing is a hypernym of deactivation; that is, firing is a word with a broader meaning than deactivation:

deactivation: breaking up a military unit (by transfers or discharges)
firing: the termination of someone's employment (leaving them free to depart)

Other hypernyms of deactivation include discharge, dismissal, dismission, liberation, release, sack, sacking.

deactivation (noun)	firing (noun)
the act of deactivating or making ineffective (as a bomb)	the act of setting something on fire
breaking up a military unit (by transfers or discharges)	the termination of someone's employment (leaving them free to depart)
	the act of discharging a gun
	the act of firing weapons or artillery at an enemy