You put your foot in your mouth.
put your foot in your mouth按字面上来讲是：“把自己的脚放到了嘴巴里”，可以联想到这个短语的正确意思是：“不小心说错话”。因此，当美国人说"You put your foot in your mouth."时他/她要表达的意思就是"You said something stupid or hurtful."、"You offended someone unconsciously by sayingsomething wrong."、"You said something unintentionally that embarrassed someone."。
Shirley: Why Jenny keeps away from me these days? Have I done something wrong?
Jane: You always hurt others by your humor. In fact, you put your foot in your mouth.
①Oh, she is so sensitive and I don't mean to hurt her.
②Small wonder she looked at me like that.
③You'd better consider how to mend it.
④Colleagues are not true friend. You should learn from it.
1. offend vt. 冒犯
He apologizes for his comments and says he had no intention of offending the community.
She is terribly offended, angered and hurt by this.
2. unintentionally adv. 无意地
Knowledge can produce equally powerful ways to destroy life, intentionally andunintentionally.
Perhaps he had slightly misled them, but it was quite unintentional.
3. embarrass vt. 使尴尬
His clumsiness embarrassed him.
It embarrassed him that he had no idea of what was going on.