riddance vs ostracism

riddance and ostracism both are nouns.

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

As nouns, ostracism is a hyponym of riddance; that is, ostracism is a word with a more specific, narrower meaning than riddance:

Other hyponyms of riddance include defenestration, deportation, barring, blackball, ouster, ousting.

riddance (noun)	ostracism (noun)
the act of forcing out someone or something	the act of excluding someone from society by general consent
the act of removing or getting rid of something	the state of being banished or ostracized (excluded from society by general consent)