Russian state media was calling Erdogan a backstabber.

之后俄罗斯国家媒体称埃尔多安“背后中伤者”。

I don't want him to think I'm a backstabber.

我不想让他认为我个背叛者。

If someone is a snake, they are a backstabber or they are untrustworthy.

如果某人蛇， 那么他们就背叛者或者不值得信任。

And what is this? Number four, backstabber!

这什么？第四， 背叛！

They are also - do you remember backstabbers?

他们也——你还记得背后捅刀子吗？

So, a " backstabber" is a person who, literally, stabs someone in the back.

所以，“背后捅刀子”指在背后捅人的人。

" Well, he's a bit of a backstabber, always trying to outdo the other guy."

“嗯，他有点背后捅刀子，总想越别人。”

This is pretty self-explanatory, I don't really feel like I need to explain backstabber, OK?

这不言自明的，我真的觉得我不需要解释背叛者， 好吗？

So, a backstabber is someone, when you turn your back, they stab you with a knife.

所以，背刺者这样的人， 当你转身时， 他们用刀刺伤你。

One of my friends is an imposter, a liar, a backstabber, sabotaging all the hard work I've done.

我的一个朋友个冒名顶替者、说谎者、背叛者，破坏了我所做的所有辛勤工作。

Ever since I started working with that obnoxious backstabber, she's done nothing but try to take the spotlight off of me and put it onto her.

自从我开始跟那个讨厌阴险的小人作，她做的就只有拼命地抢我的风头。

That would be a backstabber, to do something behind someone's back, which is another way of saying without their knowledge – without them knowing.

那将背叛者， 在某人背后做某事，这在他们不知情的情况下说的另一种说法——在他们不知情的情况下。