Definition
Occurring secretly, unexpectedly, and without being noticed.
偷偷地，出其不意地
The storm arrived like a thief in the night, taking everyone by surprise.
暴风雨像夜贼一样来袭，让所有人都措手不及。
He left the meeting like a thief in the night, and nobody noticed.
他像夜贼一样离开了会议，没有人注意到。
The company closed down like a thief in the night, without any prior warning.
公司像夜贼一样突然关闭，没有任何预警。