当头棒喝

dāng tóu bàng hè

a sharp blow or warning that brings someone to their senses

Character by character

当dāng
on

头tóu
head

棒bàng
stick

喝hè
shout

这次考试不及格，对他来说是一记当头棒喝。

Failing this exam was a real wake-up call for him.

Tone: neutral.

Chan masters are said to have struck a pupil with a stick or shouted at him to jolt him into awakening: 德山棒，临济喝. Collocations: 一记当头棒喝, 如当头棒喝.

Learn this in Lesson 90 · HSK 6–7: 佛教来到中国 (How Buddhism became Chinese)

A dialogue, a reading, word cards with audio and a drill that uses it, in Learn Chinese with Bao. The first lessons of every level are free.