husband vs househusband

husband and househusband both are nouns.

Word	Noun	Adjective	Verb	Adverb
husband	Yes	No	Yes	No
househusband	Yes	No	No	No

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

husband: a married man; a woman's partner in marriage
househusband: a husband who keeps house while his wife earns the family income

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

husband (noun)	househusband (noun)
a married man; a woman's partner in marriage	a husband who keeps house while his wife earns the family income

husband (verb)	househusband (verb)
use cautiously and frugally