loup-garou \loo-ga-ROO, noun:

A werewolf; lycanthrope.

In the bushes, the loup-garou snarled quietly, and its eyes brightened, burned with scarlet fury.
— Jim Butcher, Fool Moon

Those who were of French descent among them, and full of the old Acadian superstitions, explained it simply enough by saying he was a “loup garou,” or “were wolf,” and resigned themselves to the impossibility of contending against a creature of such supernatural malignity and power.
— Charles Roberts, “The Gray Master,” Concord Junction, 1911

Loup-garou stems from the French word of the same spelling which also means werewolf. The word loup also means “wolf” in French. It entered English in the late 1500s.