irrespective (adj.)youdaoicibaDictYouDict[irrespective 词源字典]
1620s (implied in irrespectively), "disrespectful," from assimilated form of in- (1) "not, opposite of" + respective. Meaning "without taking account of (something)" is from 1690s. Main modern use is adverbial ("irrespective of"), attested from 1839.[irrespective etymology, irrespective origin, 英语词源]