Source : Webster's Revised Unabridged Dictionary (1913)

Cantrap \Can"trap\, Cantrip \Can"trip\, n. [Cf. Icel. gandar,
   ODan. & OSw. gan, witchcraft, and E. trap a snare, tramp.]
   A charm; an incantation; a shell; a trick; adroit mischief.
   [Written also {cantraip}.] [Scot.]