married man vs cuckold

married man and cuckold both are nouns.

Word	Noun	Adjective	Verb	Adverb
married man	Yes	No	No	No
cuckold	Yes	No	Yes	No

As nouns, cuckold is a hyponym of married man; that is, cuckold is a word with a more specific, narrower meaning than married man:

Other hyponyms of married man include benedick, benedict, family man, house husband, househusband, uxoricide.

married man (noun)	cuckold (noun)
a married man; a woman's partner in marriage	a man whose wife committed adultery

married man (verb)	cuckold (verb)
	be sexually unfaithful to one's partner in marriage