beau vs coxcomb

beau and coxcomb both are nouns.

Word	Noun	Adjective	Verb	Adverb
beau	Yes	No	No	No
coxcomb	Yes	No	No	No

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

beau: a man who is much concerned with his dress and appearance
coxcomb: a conceited dandy who is overly impressed by his own accomplishments

Other hyponyms of beau include cockscomb, macaroni.

beau (noun)	coxcomb (noun)
a man who is the lover of a man or woman	the fleshy red crest on the head of the domestic fowl and other gallinaceous birds
a man who is much concerned with his dress and appearance	a cap worn by court jesters; adorned with a strip of red
	a conceited dandy who is overly impressed by his own accomplishments