unstained vs stainless

unstained is not a noun while stainless is a noun.

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

As adjectives, unstained and stainless are synonyms defined as:

Other synonyms of unstained include unsullied, untainted, untarnished.

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

unstained (adjective)	stainless (adjective)
not stained	(of reputation) free from blemishes
without soil or spot or stain
(of reputation) free from blemishes
not having a coating of stain or varnish