Two-faced speech; saying different things to different people or changing one's words depending on the situation — an idiom for duplicity or double-dealing.
彼は客の前では親切だが、裏では二枚舌だと噂されている。
He's kind in front of customers, but there's a rumor that he's two-faced behind their backs.
政治家の二枚舌に国民が怒っている。
The public is angry at the politicians' double-talk.
約束を守らないのは二枚舌のように見える。
Not keeping promises makes one appear two‑faced.