untainted vs unstained

untainted and unstained both are adjectives.

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

As adjectives, untainted and unstained are synonyms defined as:

Other synonyms of untainted include stainless, unsullied, untarnished.

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