@blablablub "turn" is one of those English words with a LOT of semi-archaic meanings or possible interpretations. I usually think of it as being used in the "to cause to rebound or recoil" sense here (turn away undead, basically)... but it could also be turn as in defection, as in turning the undead from the darkness to the light. Like casting heal on an undead or blessing a vampire when it sneezes.