Extremist group (7)

I believe the answer is:

zealots

(Other definitions for zealots that I've seen before include "Fervent or militant proponents" , "Partisans" , "Fanatics" , "Gung-ho types" , "Extreme enthusiasts" .)

I've seen this clue in The New York Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.