fanatical Syllabification: (fa·nat·i·cal)Pronunciation: /fəˈnatikəl/Translate fanatical | into German | into Italian | into Spanish Definition of fanatical adjective filled with excessive and single-minded zeal:fanatical revolutionaries obsessively concerned with something:he was fanatical about security at nightDerivatives fanaticallyPronunciation: /-(ə)lē/ adverb fanatical in other Oxford dictionaries Definition of fanatical in the British & World English dictionary