eviction vs ouster

eviction and ouster both are nouns.

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

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

eviction: the expulsion of someone (such as a tenant) from the possession of land by process of law
ouster: a wrongful dispossession

Other hyponyms of eviction include actual eviction, retaliatory eviction.

eviction (noun)	ouster (noun)
the expulsion of someone (such as a tenant) from the possession of land by process of law	the act of ejecting someone or forcing them out
action by a landlord that compels a tenant to leave the premises (as by rendering the premises unfit for occupancy); no physical expulsion or legal process is involved	a wrongful dispossession
	a person who ousts or supplants someone else