Yes. To stab someone in the back means to betray someone.

对。stab someone in the back的意思是背叛某人。

You're right. Today's expression is to stab someone in the back. Not a very nice thing to do.

没错。今天学习的表达方式是“背后伤人”。这可不是好事。

" To stab someone in the back" means to hurt someone, to deceive someone in such a way that they didn't see it coming.

“to stab someone in the back” 的意思是伤害某人，以一种他们没有看到的方式欺骗​​某人。

Literally, " to stab someone in the back" would be to take a knife and put it into the back of the person, obviously trying to kill them.

从字面上看，“to stab someone in the back” 就是拿刀插在人的后背上， 显然是想杀死他们。