Source : Webster's Revised Unabridged Dictionary (1913)

Fanaticism \Fa*nat"i*cism\, n. [Cf. {Fanatism}.]
   Excessive enthusiasm, unreasoning zeal, or wild and
   extravagant notions, on any subject, especially religion;
   religious frenzy.

Source : WordNet®

fanaticism
     n : excessive intolerance of opposing views [syn: {zealotry}]