na-adjective, noun
fanatic; zealot
Describes a person with extreme, uncritical enthusiasm or devotion, often for a cause, belief, or hobby. Used as both a noun and a na-adjective.
彼はサッカーのファナティックで、週末は必ずスタジアムに行く。
He is a soccer fanatic and goes to the stadium every weekend without fail.
あの政治家
The fanatical supporters of that politician refuse to listen to any criticism.