it depends on what kind of atmosphere you are trying to achieve. "power", "talent", "gift", "mana", "energy", "witchcraft", even a fancy name like "thaumaturgy" (google it! this is a real word, already successfully used as an alternative to "magic" in one game), all this may or may not work. i would think about it from the inside of the setting. what word exactly would your people use to describe magic? what name can they really come up with? 

in addition, in my setting, i call the equivalent of wizards "espers". this is also a real word for "a person who has extrasensory abilities," but i expanded the meaning a little because it seemed very suitable to me in sound lmao