ostracism vs expulsion

ostracism and expulsion both are nouns.

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

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

Other hypernyms of ostracism include ejection, exclusion, riddance.

ostracism (noun)	expulsion (noun)
the act of excluding someone from society by general consent	the act of expelling or projecting or ejecting
the state of being banished or ostracized (excluded from society by general consent)	the act of forcing out someone or something
	squeezing out by applying pressure