: very or overly enthusiastic or devoted <a fanatic supporter>
Word History of FANATIC
In Latin the adjective fanaticus, a derivative of fanum, “temple,” meant literally “of a temple,” though the more common sense was “inspired by a god” or “frenzied.” The word was borrowed into English as fanatic in the 1500s with this sense. In the following century the word was applied to members of certain Protestant groups who argued for their beliefs—in the view of most people—with excessive enthusiasm, acting as if they were divinely inspired. Eventually, fanatic was applied to anyone who showed extreme devotion to a cause.