表ㄅㄧㄠˇbiǎo裡ㄌㄧˇlǐ不ㄅㄨˋbù一ㄧyī

  1. 內外不一致，指思想和言行相反不一致。如：「不要聽信他的話，他是表裡不一的人。」

英outside appearance and inner reality differ (idiom)​; not what it seems, saying one thing but meaning sth different