磨破嘴皮子

mópòzuǐpízi ㄇㄛˊ ㄆㄛˋ ㄗㄨㄟˇ ㄆㄧˊ ˙ㄗ

    • to wear out one's lips (idiom)
    • to talk until one is blue in the face
    • to repeat again and again

Character by character

Saying俗语俗語

Idiom惯用语 · In everyday use

Literally
wear through the lips
Meaning
Talk until you're worn out; use up all one's words trying to persuade someone.

Sources