fanatic; zealot; fervent believer
Refers to a person with extreme, uncritical enthusiasm for a cause, ideology, or person. Often carries a negative connotation of blind devotion.
He is a fanatical follower of that new religion.
The fanatics take the leader's words as absolute truth.
Compound of 熱狂的 (nekkyōteki, 'enthusiastic, fanatical') + 信者 (shinja, 'believer, follower'). The word is a straightforward combination of its parts.