two-faced
adjective disapproving uk/ˌtuːˈfeɪst/ us/ˌtuːˈfeɪst/
两面派的;当面一套背后一套的
Someone who is two-faced is not sincere, saying unpleasant things about you to other people while seeming to be pleasant when they are with you.
I don't trust her - I suspect she's a bit two-faced. 我不信任她——我觉得她有点虚伪。
Synonym: duplicitous