放冷枪

Traditional (Taiwan): 放冷槍

fànglěngqiāng ㄈㄤˋ ㄌㄥˇ ㄑㄧㄤ

    • to attack or criticise someone by surprise from hiding

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
fire a cold shot
Meaning
To attack or criticise someone from hiding, by surprise; same as 打冷枪.

Sources