mellow vs mellowing

mellow is not a noun while mellowing is a noun.

Word	Noun	Adjective	Verb	Adverb
mellow	No	Yes	Yes	Yes
mellowing	Yes	No	No	No

mellow (noun)	mellowing (noun)
	the process of becoming mellow

mellow (adjective)	mellowing (adjective)
slightly and pleasantly intoxicated from alcohol or a drug (especially marijuana)
unhurried and relaxed
having a full and pleasing flavor through proper aging
softened through age or experience

mellow (verb)	mellowing (verb)
make or grow (more) mellow
soften, make mellow
become more relaxed, easygoing, or genial

mellow (adverb)	mellowing (adverb)
in a mellow manner