One who is politically active in the role of a citizen; especially, one who campaigns for change.
One who is conspicuously active in carrying out any occupational or professional functions.
Behaving as an activist.
A young person who agitates for political or other reform; a young person with a rebellious disposition.
From the late-19th to the early-20th century, a member of a movement that campaigned for reform of the Ottoman Empire.