Meaning

noun a monster able to change appearance from human to wolf and back again

originFrom Middle English werwolf, from Old English werewulf, from Proto-West Germanic *werawulf, from Proto-West Germanic *wer (“man”) + *wulf (“wolf”). Cognate with Dutch weerwolf, Low German Warwulf, German Werwolf, Danish varulv, Swedish varulv, and even possibly Finnish vironsusi. By surface analysis, were- + wolf. * Compare French garou in loup-garou; French dialectal gairou, varou (“werewolf”);…

Etymology from Wiktionary, CC BY-SA 3.0