vocalizing vs singing

vocalizing and singing both are nouns.

Word	Noun	Adjective	Verb	Adverb
vocalizing	Yes	No	No	No
singing	Yes	Yes	No	No

As nouns, vocalizing and singing are synonyms defined as:

vocalizing (noun)	singing (noun)
the act of singing vocal music	the act of singing vocal music
	disclosing information or giving evidence about another

vocalizing (adjective)	singing (adjective)
	smooth and flowing