French leave
noun
mass noun
- informal, dated absence from work or duty without permission〈非正式, 旧〉不辞而别; 擅自缺席。
词源
mid 18th cent.: said to derive from the French custom of leaving a dinner or ball without saying goodbye to the host or hostess. The phrase was first recorded shortly after the Seven Years War; the equivalent French expression is filer à l'Anglaise, literally 'to escape in the style of the English'.