untainted vs stainless

untainted is not a noun while stainless is a noun.

Word	Noun	Adjective	Verb	Adverb
untainted	No	Yes	No	No
stainless	Yes	Yes	No	No

As adjectives, untainted and stainless are synonyms defined as:

Other synonyms of untainted include unstained, unsullied, untarnished.

untainted (noun)	stainless (noun)
	steel containing chromium that makes it resistant to corrosion

untainted (adjective)	stainless (adjective)
(of reputation) free from blemishes	(of reputation) free from blemishes