double-crosser

Everyone thought he was a loyal friend, but he turned out to be a double-crosser.

大家都认为他是忠诚的朋友，结果却发现他是个骗子。

用法提示：本句中 double-crosser 作名词，意为背信弃义的人。

I can't trust any information from her because she is known as a double-crosser.

我不能相信她提供的任何信息，因为她是个出了名的出卖人。

用法提示：本句中 double-crosser 作名词，形容不值得信任的骗子。

The gang discovered there was a double-crosser among them who had been feeding information to the police.

那个团伙发现他们中间有一个出卖人，一直在向警方提供情报。

用法提示：本句中 double-crosser 作名词，指内奸或告密者。