A magician does magic tricks. You might hire a magician to pull rabbits out of hats and do card tricks at your next birthday party.
A performer whose specialty is sleight-of-hand and other illusions is one kind of magician. Another magician is the kind who makes real magic, casting spells and summoning spirits. More people believe in the first kind of magician — who is simply pretending to do magic — than the second. The word stems from the Old French magiciien, "magician or sorcerer," which is rooted in the Greek word for "magical," magikos.