untainted (adj.)youdaoicibaDictYouDict[untainted 词源字典]
1580s, in the moral sense; c. 1600 in the physical sense; from un- (1) "not" + past participle of taint (v.). Earlier was untained (mid-15c.), from a Middle English variant of taint (v.).[untainted etymology, untainted origin, 英语词源]