cantrip |ˈkantrip|noun Scottish, archaica mischievous or playful act; a trick.ORIGIN late 16th cent. (also in the sense [witch's trick]): of unknown origin.
I came across this word recently in Mike Carey's novel, The Devil You Know. The book was a mixed experience--nice prose, but by Jove, the story moved like molasses. I was listening to the audiobook and my mind kept wandering off. That never happens when the story is interesting.