mild vs mildness

mild is not a noun while mildness is a noun.

Word	Noun	Adjective	Verb	Adverb
mild	No	Yes	No	No
mildness	Yes	No	No	No

mild (noun)	mildness (noun)
	mercifulness as a consequence of being lenient or tolerant
	acting in a manner that is gentle and mild and even-tempered
	good weather with comfortable temperatures

mild (adjective)	mildness (adjective)
moderate in type or degree or effect or force; far from extreme
mild and pleasant
humble in spirit or manner; suggesting retiring mildness or even cowed submissiveness