scat vs scat singing

scat and scat singing both are nouns.

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

As nouns, scat and scat singing are synonyms defined as:

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

scat (noun)	scat singing (noun)
singing jazz; the singer substitutes nonsense syllables for the words of the song and tries to sound like a musical instrument	singing jazz; the singer substitutes nonsense syllables for the words of the song and tries to sound like a musical instrument

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