From Longman Dictionary of Contemporary Englishcampaignercam‧paign‧er /kæmˈpeɪnə $ -ər/  ●○○ noun [countable]  someone who leads or takes part in actions which are intended to achieve a particular social or political resultcampaigner for a campaigner for greater democracypeace/human rights/environmental campaigners 
                                                    
                                                
