暗箭傷人 [－－伤－]

Jyutping am3 zin3 soeng1 jan4
Pinyin àn jiàn shāng rén

Definitions (CC-CANTO)
  1. to stab someone in the back unexpectedly
Definitions (Wiktionary)
  1. phrase, idiomatic
    to injure someone with unscrupulous or underhand means; to backstab