detachment (n.)youdaoicibaDictYouDict[detachment 词源字典]
1660s, "action of detaching," from French détachement (17c.), from détacher (see detach). Meaning "portion of a military force" is from 1670s; that of "aloofness from objects or circumstances" is from 1798.[detachment etymology, detachment origin, 英语词源]