揪辫子

Traditional (Taiwan): 揪辮子

jiūbiànzi ㄐㄧㄡ ㄅㄧㄢˋ ˙ㄗ

    • to grab sb by the queue (i.e. hair)
    • to seize on weak points
    • to exploit the opponent's shortcomings

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
pull someone's braid
Meaning
To seize on someone's faults or mistakes as a handle to attack them. Critical.

Sources