unawares (adv.)youdaoicibaDictYouDict[unawares 词源字典]
1530s, "without being aware," from un- (1) "not" + aware + adverbial genitive -s. Meaning "without being noticed" is recorded from 1660s. Form unaware is recorded from 1590s.[unawares etymology, unawares origin, 英语词源]