scat vs singing

scat and singing both are nouns.

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

As nouns, singing is a hypernym of scat; that is, singing is a word with a broader meaning than scat:

scat: singing jazz; the singer substitutes nonsense syllables for the words of the song and tries to sound like a musical instrument
singing: the act of singing vocal music

Other hypernyms of scat include vocalizing, jazz.

scat (noun)	singing (noun)
singing jazz; the singer substitutes nonsense syllables for the words of the song and tries to sound like a musical instrument	the act of singing vocal music
	disclosing information or giving evidence about another

scat (adjective)	singing (adjective)
	smooth and flowing

scat (verb)	singing (verb)
flee; take to one's heels; cut and run