This is not a commonly-used word -- it's probably outdated, if not actually antiquated. I've found it in a couple of places on the Internet, but not in any dictionaries (other than Webster, down there, and that old boy's gotta be senile by now) and never in any scholarly work on werewolves (and I've read a lot of 'em).

If you want to consider it a real word, let's say that it means "a person who, through sorcery or a pact with the devil, has gained the ability to transform into a wolf." For any generic werewolf, just call him (or her) a lycanthrope.

Ly*can"thro*pist (?), n.

One affected by the disease lycanthropy.

© Webster 1913.