singer vs vocalizer

singer and vocalizer both are nouns.

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

As nouns, singer and vocalizer are synonyms defined as:

Other synonyms of singer include vocaliser, vocalist.

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