1. (n.) The leader of a circle of dancers; hence, the leader of a number of persons acting together; the leader of a herd of animals.

2. (n.) Opprobriously, a leader of a body of men engaged in the violation of law or in an illegal enterprise, as rioters, mutineers, or the like.

Mahdi agent provocateur agitator agitprop bell cow bell mare bellwether born leader boss cacique catalyst charismatic leader choirmaster choragus conductor coryphaeus demagogue duce exciter file leader firebrand fomenter forerunner fugleman incendiary inciter inflamer inspired leader instigator keynoter leader leader of men man higher up messiah mischief-maker pacemaker pacesetter policy maker precentor provocateur provoker rabble-rouser rouser sachem seditionary seditionist standard-bearer symphonic conductor torchbearer troublemaker urger