caroler vs vocalizer

caroler and vocalizer both are nouns.

Word	Noun	Adjective	Verb	Adverb
caroler	Yes	No	No	No
vocalizer	Yes	No	No	No

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

Other hypernyms of caroler include singer, vocaliser, vocalist.

caroler (noun)	vocalizer (noun)
a singer of carols	a person who sings
	an organism that can utter vocal sounds