deactivation vs dismission

deactivation and dismission both are nouns.

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

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

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

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

deactivation (noun)	dismission (noun)
the act of deactivating or making ineffective (as a bomb)	the termination of someone's employment (leaving them free to depart)
breaking up a military unit (by transfers or discharges)	official notice that you have been fired from your job