ouster vs expulsion

ouster and expulsion both are nouns.

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

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

Other hypernyms of ouster include ejection, exclusion, riddance.

ouster (noun)	expulsion (noun)
the act of ejecting someone or forcing them out	the act of expelling or projecting or ejecting
a wrongful dispossession	the act of forcing out someone or something
a person who ousts or supplants someone else	squeezing out by applying pressure