Crossword Genius

Leading trouble-maker (10)

Ross

I believe the answer is:

ringleader

(Other definitions for ringleader that I've seen before include "Chief troublemaker" , "firebrand" , "Mastermind" , "One heading up illicit activity" , "Main villain" .)

I've seen this clue in the Sydney Morning Herald.
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.