A devious, cunning, and/or mischievous person. ("Devil" here is not intended to indicate an evil or malevolent person, but rather to emphasize "crafty.") Tabloid reporters are such crafty devils, spinning people's personal problems into sensationalist stories. He's a crafty devil in business, cleverly negotiating deals with and between companies that would normally be in fierce competition with one another.

Exceptionally clever, cunning, or shrewd, especially in devious or underhanded ways. He thought he was being crafty as a fox in the way he had been skimming money from the cash registers, but management caught up with him eventually. The novel centers around the cat-and-mouse chase between a police detective and a thief who is as crafty as a fox. She may come off as nothing but smiles and sunshine, but trust me—she's crafty as a fox!