wash one's dirty linen in public 字面意思是当众洗脏床单，比喻在大庭广众之下把不好让别人知道的事情张扬出去。也可以用 air 代替 wash 。

Uncle Albert has been to prison three times for theft. Father often warns us not to mention his name in the presence of strangers so as not to wash his dirty linen in public. 艾伯特叔叔因偷窃曾三次入狱，父亲常常警告我们在陌生人外面不要提他，免得家丑外扬。

That lady does not seem to mind airing her dirty linen in public. She is talking so loudly on the bus about her quarrel with her husband. 那位太太好像不在意别人知道她的隐私，她居然在公共汽车上大声谈论她和她丈夫之间的争吵。