Definition from Wiktionary, the free dictionary
campaigner (plural campaigners)
- A person who has served in a military campaign.
- (by extension) A military veteran.
- A person who campaigns for a person running for political office.
- Someone with experience in a certain field.
- An activist.
2013 June 21, Karen McVeigh, “US rules human genes can't be patented”, in The Guardian Weekly, volume 189, number 2, page 10:
- The US supreme court has ruled unanimously that natural human genes cannot be patented, a decision that scientists and civil rights campaigners said removed a major barrier to patient care and medical innovation.