wolf in sheep's clothing

1. Figuratively, anyone who disguises a ruthless nature through an outward show of innocence. Jesus taught his followers to “beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.”

Idioms and Phrases

An enemy disguised as a friend, as in Dan was a wolf in sheep's clothing, pretending to help but all the while spying for our competitors. This term comes from the ancient fable about a wolf that dresses up in the skin of a sheep and sneaks up on a flock. This fable has given rise to a rich history of allusions as in the Sermon on the Mount when Jesus speaks of false prophets in sheep's clothing, “but inwardly they are ravening wolves” (Matthew 7:15).

Related Words

• bigot 
• charlatan 
• crook 
• impostor 
• phony 
• trickster