rapper vs vocalizer

rapper and vocalizer both are nouns.

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

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

Other hypernyms of rapper include singer, vocaliser, vocalist.

rapper (noun)	vocalizer (noun)
a device (usually metal and ornamental) attached by a hinge to a door	a person who sings
someone who performs rap music	an organism that can utter vocal sounds