1. a person who works actively to achieve a particular goal, especially in politics or social causes
2. a person who takes part in a military campaign
Usage: military

Examples

• She is a dedicated campaigner for environmental protection.
• The civil rights campaigner spoke passionately about equality.
• He became a campaigner against poverty in his community.
• The seasoned campaigner knew how to rally voters.
• Anti-war campaigners gathered outside the government building.
• The veteran campaigner had served in three different conflicts.
• Local campaigners organized a petition to save the park.