释义：

shirt 衬衫，衬衣，字面来看，Keep your shirt on 穿上衬衫的意思；

In English, To keep calm. 在英文里，是保持冷静，别激动的意思； If we find ourselves in a heated situation with a person getting riled up, we may try calming the irritated person by using this expression.如果我们发现周围有人发怒或者生气了，我们就可以用keep your shirt on去让他保持冷静；

来源：

This phrase may originate from the fact that when people get angry and are looking to fight, they'll sometimes remove their shirt. 这个俚语的来源是这样子，当人们很生气，准备打架的时候，他们就会脱掉自己的衬衣。Why? Because removing one's shirt increases maneuverability；为什么呢，因为脱掉衣服就可以增加灵活性。it allows for further range of motion of the upper body that would otherwise be limited.这样打架时上肢的运动就会更加自如；Therefore, those who were not interested in fighting would advise an angered person to literally keep their shirt on, showing they wanted to settle things through peaceful means rather than through violence.因此，对打架不是很感兴趣的人就会建议打架者穿上衣服，以此暗示他们希望打架者通过和平而不是暴力的形式来解决问题。

举例：

1.你和朋友去赶车，朋友的时间计算错了，很着急，你就可以说：

keep your shirt on, we have plenty of time to catch the train.

你别太紧张了，我们还有时间足够赶到火车。

2.这学期没好好学习，考试考了59分，老爸很生气，你说：

Dad, keep your shirt on, please! I'll study hard next term.爸爸，千万不要发火，我下学期一定努力学习。