Origin and history of lycanthropy

Middle English werwolf, from late Old English werewulf, in old superstition, "person with the power to supernaturally transform into a wolf while retaining human intelligence," from wer "man, male person" (from PIE root *wi-ro- "man") + wulf (see wolf (n.); also see here for the mythology).

Belief in them was widespread in the Middle Ages. Sometimes the transformation was accomplished by means of a magic girdle. Similar formation in Middle Dutch weerwolf, Old High German werwolf, Swedish varulf.

An old word rare from 17c. (mostly in Scottish), broadly revived early 19c. in folklore studies. Another old word for it was witch-wolf. From this use were- was extended by 1873 to other similar supernatural creatures (-bear, in South America jaguar, in earliest use -ass).

In the ancient Persian calendar, the eighth month (October-November) was Varkazana-, "(Month of the) Wolf-Men." Related: Werewolfism. Middle English had wolfling (c. 1300) for a centaur-like creature part wolf, part human.

larger carnivorous canine of the Old World, hunting in packs, destructive to farm animals, and occasionally attacking humans; Middle English, from Old English wulf "wolf; wolfish person, devil," from Proto-Germanic *wulfaz, from PIE root *wlkwo- "wolf."

This is reconstructed to also be the source of Sanskrit vrkas, Avestan vehrka-; Albanian ul'k; Old Church Slavonic vluku; Russian volcica; Lithuanian vilkas "wolf;" probably also Greek lykos, Latin lupus. Germanic cognates include Old Saxon wulf, Old Norse ulfr, Old Frisian, Dutch, Old High German, German wolf, Gothic wulfs. Old Persian Varkana- is "Hyrcania," district southeast of the Caspian Sea, literally "wolf-land;"

The type of a predator, it was commonly contrasted to sheep; in reference to persons in Middle English it denotes rapacity, ferocity, one who preys on the innocent or powerless. Also a complimentary word for a warrior in Germanic given names, as Adolf, Rudolph. The animal probably was driven to extinction in England by the end of the 15th century, in Scotland by the early 18th. The U.S. gray wolf is a different and larger species.

Wolves as a symbol of lust are ancient, such as Roman slang lupa "whore," literally "she-wolf" (preserved in Spanish loba, Italian lupa, French louve). The equation of "wolf" and "prostitute, sexually voracious female" persisted (wolfesse glosses Latin lupa late 14c.), but by Elizabethan times wolves had become primarily symbolic of male lust.

The specific use of wolf for "sexually aggressive male" is attested by 1847. Colloquial wolf-whistle is attested by 1945, American English, at first associated with sailors ashore.

The image of a wolf in sheep's skin is attested in English by c. 1400.

This haue be feyned religiows ypocrites with here disgised clothes, þat had the lambe is skyn upon hem selffe be semyng with owt, but withinforth thei were ravisshing wolffes. ["The Pilgrimage of the Soul," early 15c.]

To cry wolf "raise a false alarm" is by 1812, from the well-known moral story of the shepherd boy (attested in English by 1690s). To keep the wolf from the door "keep out hunger or want" is by late 15c.

This manne can litle skyl ... to saue himself harmlesse from the perilous accidentes of this world, keping ye wulf from the doore (as they cal it). ["The Institution of a Gentleman," 1555]

The wolf-spider (the European tarantula) is so called by c. 1600, for prowling and leaping on its prey rather than waiting in a web. Figurative throw (someone) to the wolves is by 1927, on the notion of putting off pursuit by sacrificing one of the pursued.