inmarriage vs matrimony

inmarriage and matrimony both are nouns.

Word	Noun	Adjective	Verb	Adverb
inmarriage	Yes	No	No	No
matrimony	Yes	No	No	No

As nouns, matrimony is a hypernym of inmarriage; that is, matrimony is a word with a broader meaning than inmarriage:

inmarriage: marriage within one's own tribe or group as required by custom or law
matrimony: the state of being a married couple voluntarily joined for life (or until divorce)

Other hypernyms of inmarriage include marriage, spousal relationship, union, wedlock.

inmarriage (noun)	matrimony (noun)
marriage within one's own tribe or group as required by custom or law	the ceremony or sacrament of marriage
	the state of being a married couple voluntarily joined for life (or until divorce)