let their hair down

• vi. 不拘礼节(态度随便)

let their hair down的用法和样例：

例句

用作不及物动词 (vi.)

1. It's wonderful to let your hair down at the weekend after you've been working hard all week.
   辛苦工作一周後在周末不拘礼节轻松一下真是太好了。