stab in the back
背后刺一刀
口语·表达背叛或欺骗
英文释义
to betray or deceive someone, especially in a sneaky or underhanded way
例句
I can't believe my best friend stabbed me in the back by spreading rumors about me at work.
典故来源
源自战场上的背刺行为，比喻暗中背叛或出卖信任自己的人。