阴阳脸

Traditional (Taiwan): 陰陽臉

yīnyángliǎn ㄧㄣ ㄧㄤˊ ㄌㄧㄢˇ

    • two-faced person
    • showing one face to someone's face and another behind their back

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
yin-yang face
Meaning
Showing one face to someone's face and another behind their back; two-faced. Critical.

Sources