adjective / noun
militant
MIL-ih-tunt/mˈɪlʌtʌnt/
Forcefully supporting a political or social cause, sometimes through violence, or a person who does so.
The union takes a militant stand against unsafe working conditions.

Etymology
Originally describing someone serving as a soldier or fighting, militant extended the image of combat to supporting a cause, especially through direct action.
In context
a host of other militant groups to continue to fight us there
More examples
- She is a militant advocate for equal pay.
- The group's militants favor strikes and sit-ins over quiet negotiations.
- Armed militants seize control of the border crossing.
Forms
militant · militants
militancy noun — Forceful, aggressive support for a cause.
militantly adverb — In a forceful, aggressively committed manner.
Similar words
- activist
- Someone working for change, not necessarily aggressively or violently.
- combative
- Eager to fight or argue, not necessarily for a cause.