掉链子

Traditional (Taiwan): 掉鏈子

diàoliànzi ㄉㄧㄠˋ ㄌㄧㄢˋ ˙ㄗ

    • to have one's bicycle chain come off
    • to let sb down to drop the ball to screw up

      fig.

Character by character

Saying俗语俗語

Idiom惯用语 · In everyday use

Literally
the chain falls off
Meaning
To fail at a crucial moment, as a link in a process breaks down. Commonly said of someone who lets the team down.

Sources