ousting vs expulsion

ousting and expulsion both are nouns.

Word	Noun	Adjective	Verb	Adverb
ousting	Yes	No	No	No
expulsion	Yes	No	No	No

As nouns, expulsion is a hypernym of ousting; that is, expulsion is a word with a broader meaning than ousting:

Other hypernyms of ousting include ejection, exclusion, riddance.

ousting (noun)	expulsion (noun)
the act of ejecting someone or forcing them out	the act of expelling or projecting or ejecting
	the act of forcing out someone or something
	squeezing out by applying pressure