開冷槍

Simplified: 开冷枪

kāilěngqiāng ㄎㄞ ㄌㄥˇ ㄑㄧㄤ

    • to attack someone unexpectedly
    • to take a cheap shot

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
fire a cold shot
Meaning
To attack someone unexpectedly, especially from hiding, with a surprise criticism or blow. Critical. Close to "take a cheap shot".

Sources