unaccompanied (adj.)youdaoicibaDictYouDict[unaccompanied 词源字典]
1540s, "not in the company of others, having no companions," from un- (1) "not" + past participle of accompany (v.). Musical sense "without instrumental accompaniment" is first recorded 1818.[unaccompanied etymology, unaccompanied origin, 英语词源]