mixed marriage vs marriage

mixed marriage and marriage both are nouns.

Word	Noun	Adjective	Verb	Adverb
mixed marriage	Yes	No	No	No
marriage	Yes	No	No	No

As nouns, marriage is a hypernym of mixed marriage; that is, marriage is a word with a broader meaning than mixed marriage:

mixed marriage: marriage of two people from different races or different religions or different cultures
marriage: two people who are married to each other

Other hypernyms of mixed marriage include man and wife, married couple.

mixed marriage (noun)	marriage (noun)
marriage of two people from different races or different religions or different cultures	the act of marrying; the nuptial ceremony
	two people who are married to each other
	the state of being a married couple voluntarily joined for life (or until divorce)
	a close and intimate union