fanatic

a. [ L. fanaticus inspired by divinity, enthusiastic, frantic, fr. fanum fane: cf. F. fanatique. See Fane. ] Pertaining to, or indicating, fanaticism; extravagant in opinions; ultra; unreasonable; excessively enthusiastic, especially on religious subjects; as, fanatic zeal; fanatic notions. [ 1913 Webster ]

But Faith, fanatic Faith, once wedded fast
To some dear falsehood, hugs it to the last. T. Moore. [ 1913 Webster ]

n. A person affected by excessive enthusiasm, particularly on religious subjects; one who indulges wild and extravagant notions of religion. [ 1913 Webster ]

There is a new word, coined within few months, called fanatics, which, by the close stickling thereof, seemeth well cut out and proportioned to signify what is meant thereby, even the sectaries of our age. Fuller (1660). [ 1913 Webster ]

Fanatics are governed rather by imagination than by judgment. Stowe. [ 1913 Webster ]

a. Characteristic of, or relating to, fanaticism; fanatic. -Fa*nat"ic*al*ly, adv. -- Fa*nat"ic*al*ness, n. [ 1913 Webster ]

n. [ Cf. Fanatism. ] Excessive enthusiasm, unreasoning zeal, or wild and extravagant notions, on any subject, especially religion, politics or ideology; religious frenzy.

Syn. -- See Superstition. [ 1913 Webster ]