A magician is someone who purports to make use of magic, either for the entertainment of others or for their own amusement.
Dr. Leonard McCoy claimed that he was "not a magician" when asked by Spock to treat his sensitivity to cold in 2267. McCoy had been thus far unable to determine a method of treatment for the accelerated aging he and other crew members were suffering from. (TOS: "The Deadly Years")
Harry Houdini was a famous magician from Earth. According to Jonathan Archer, he could escape from virtually any restraint, an ability he thought would have been useful when he and T'Pol were captured by Coridan dissidents in 2151. (ENT: "Shadows of P'Jem")