purr vs make vibrant sounds

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

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

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

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

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

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