removal vs dismission

removal and dismission both are nouns.

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

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

removal: dismissal from office
dismission: the termination of someone's employment (leaving them free to depart)

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

removal (noun)	dismission (noun)
the act of removing	the termination of someone's employment (leaving them free to depart)
dismissal from office	official notice that you have been fired from your job