放冷箭
Stab in the back.

【发音】fàng lěng jiàn

【释义】（惯）喻指暗中加害于人的行为或手段。又称“射冷箭”。
            Used as a metaphor to refer to playing tricks behind sb.'s back, or secretly getting sb. into trouble.

【例1】他就会背后放冷箭，真让人火大。
           He often stabs people in the back, which enrages me.

【例2】卑怯而狡猾的懦夫则往往想要暗中施放的冷箭。
           base and crafty cowards, are like the arrow that shoots in the dark.