ETYM Latin fanaticus inspired by divinity, enthusiastic, frantic, from fanum fane: cf. French fanatique. Related to Fane.
Marked by excessive enthusiasm for and intense devotion to a cause or idea; SYN. fanatical, overzealous, rabid.
fanatical · overzealous · passionate · rabid
A person motivated by irrational enthusiasm (as for a cause); SYN. fiend.