Wolf in sheep's clothing
形容外表友善、内心险恶的人，伪装成无害者以欺骗他人。
警告他人提防伪君子。
英文释义
A person who pretends to be nice but is not
例句
He seemed kind, but turned out to be a wolf in sheep's clothing.
典故来源
源自《伊索寓言》，狼披羊皮混入羊群，比喻伪善者。