赌博可是一件非常危险的事情，一不小心就可能会倾家荡产，失去所有。表达“lose one's shirt 失去衬衫“很形象地形容了一个人由于赌博或在高风险投资项目中失败而输掉所有的财产，包括自己穿的衬衫，变得一无所有。
(图片来自BBC Learning English)
I lost my shirt on a bad investment. I didn’t realize that it was a scam.
I don’t want to go to Las Vegas. I’m worried I’d lose my shirt in the casinos.
If you don’t know what you’re doing it’s very easy to lose your shirt on the stock market.
另一个和“衬衫“相关的表达是“keep your shirt on 穿着你的衬衫“。这个表达的实际含义是劝说某人要保持冷静，在对情况有所了解之前不要激动或生气。
Alright, keep your shirt on! I said I was sorry I was late.
Keep your shirt on. No need to get angry. I am going to do the washing, I just need to finish my magazine first.