抹锅灰

Traditional (Taiwan): 抹鍋灰

mǒguōhuī ㄇㄛˇ ㄍㄨㄛ ㄏㄨㄟ

    • to disgrace someone
    • to blacken someone's name

Character by character

Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
smear pot soot
Meaning
To disgrace or blacken someone's name, making them look bad or shaming them. Critical.

Sources