Absent without leave means to be away without permission or explanation. The term and its acronym¹, AWOL, originated in the American military during World War I for soldiers absent from duty without permission (leave). It later was transferred to civilian² situations.

Note:

Absent without leave的意思为擅离职守，原本是一战时期的军事用语，后在日常生活中的到流传。Leave在这里是“请假”的意思。

例： Her daughter went to the mall but got in trouble for being absent without leave. 妈妈很生气女儿没打招呼就擅自去逛商场。