make vibrant sounds vs purr

make vibrant sounds is not a noun while purr is a noun.

Word	Noun	Adjective	Verb	Adverb
make vibrant sounds	No	No	Yes	No
purr	Yes	No	Yes	No

As verbs, make vibrant sounds and purr are synonyms defined as:

make vibrant sounds and purr: indicate pleasure by purring; characteristic of cats

make vibrant sounds (noun)	purr (noun)
	a low vibrating sound typical of a contented cat

make vibrant sounds (verb)	purr (verb)
indicate pleasure by purring; characteristic of cats	indicate pleasure by purring; characteristic of cats
	make a soft swishing sound