Middle English, from Old English werwulf (akin to Old High German werwolf werewolf), from wer man + wulf wolf — more at virile, wolf
First Known Use: before 12th century
Lon Chaney, Jr., as a werewolf in The Wolf Man (1941).—Courtesy of Universal Pictures; photograph, Lincoln Center Library of the Performing Arts, New York Public Library
In European folklore, a man who changes into a wolf at night and devours animals, people, or corpses, returning to human form by day. Some werewolves are thought to change shape at will; others, who inherited the condition or acquired it by being bitten by a werewolf, are transformed involuntarily under the influence of a full moon. Belief in werewolves is found throughout the world and was especially common in 16th-century France. Humans who believe they are wolves suffer from a mental disorder called lycanthropy.