Late Old English werewulf; the first element has usually been identified with Old English wer 'man'. In modern use the word has been revived through folklore studies.

• wolf from Old English:

  The Indo-European root of wolf also gave rise to Greek lukos and Latin lupus, the source of lupine (mid 17th century), ‘like a wolf’. The Greek word gave us lycanthropy (mid 16th century), the mythical transformation of a person into a wolf or werewolf (Old English): the were- part of werewolf is probably from wer, the Old English word for ‘man’ or ‘person’, just as the second half of the Greek comes from anthropos ‘man’ (see world).

  The story of the shepherd boy who thought it would be funny to cause a panic by falsely crying ‘wolf!’ is one of the fables of Aesop, the Greek storyteller of the 6th century bc. To keep the wolf from the door is to have enough money to avoid starvation: the phrase has been used since the 15th century. To throw someone to the wolves, or leave them to be roughly treated, is surprisingly recent though, being recorded only from the 1920s. The image here is of travellers on a sledge who are set upon by a pack of wolves, and decide to throw out one of their number to lighten the load and allow themselves to make their escape. A wolf in sheep's clothing is a person or thing that appears friendly or harmless but is really hostile. This comes from the Sermon on the Mount, as recounted in the Gospel of Matthew, when Jesus says: ‘Beware of false prophets, which come to you in sheep's cloth, but inwardly they are ravening wolves.’