vigorously active and aggressive, esp. in support of a cause

militant reformers.

engaged in warfare; fighting.

a militant person.

a person engaged in warfare or combat.

adjective

compliant , peaceful , peaceloving , submissive , tolerant

adjective

active , assertive , assertory , bellicose , belligerent , combating , contending , contentious , embattled , fighting , gladiatorial , in arms , martial , militaristic , military , offensive , pugnacious , pushy , quarrelsome , scrappy , self-assertive , truculent , up in arms , vigorous , warlike , warring , combatant , hostile , combative

noun

activist , belligerent , combatant , demonstrator , fighter , objector , partisan , protester , rioter , warrior , aggressive , combative , defiant , martial , soldier , warlike , warring