DictionarymilitantAggressive support for a cause
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.

An impassioned civic campaigner speaks forcefully with clenched fist at a small peaceful rally, fellow advocates listening; assertive activism without weapons, flags, writing or slogans.
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

United States Institute of Peace83:42
a host of other militant groups to continue to fight us there
U.S. Leverage in South Asia

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.