complacence (n.)youdaoicibaDictYouDict[complacence 词源字典]
mid-15c., "pleasure," from Medieval Latin complacentia "satisfaction, pleasure," from Latin complacentem (nominative complacens), present participle of complacere "to be very pleasing," from com-, intensive prefix (see com-), + placere "to please" (see please). Sense of "pleased with oneself" is 18c.[complacence etymology, complacence origin, 英语词源]