unfriendly (adj.)youdaoicibaDictYouDict[unfriendly 词源字典]
early 15c., "not characteristic of friends, hostile, inimical," from un- (1) "not" + friendly. Similar formation in Middle Dutch onvriendelijc, Middle High German unvriuntlich, German unfreundlich. Old English had unferondlice "unkindly." Related: Unfriendliness.[unfriendly etymology, unfriendly origin, 英语词源]