poet-singer vs vocalizer

poet-singer and vocalizer both are nouns.

Word	Noun	Adjective	Verb	Adverb
poet-singer	Yes	No	No	No
vocalizer	Yes	No	No	No

As nouns, vocalizer is a hypernym of poet-singer; that is, vocalizer is a word with a broader meaning than poet-singer:

Other hypernyms of poet-singer include singer, vocaliser, vocalist.

poet-singer (noun)	vocalizer (noun)
a singer of folk songs	a person who sings
	an organism that can utter vocal sounds