A proponent or practitioner of activism: political activists. (noun)
Of, relating to, or engaged in activism.(adjective)
Of, relating to, or being an activist.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "activist" in a sentence
"I think people can be confused by the term "activist"."
"You know, the term activist judge wearing its hat again with the nomination of Sonia Sotomayor to the Supreme Court."
"So, Carol, we hear the term activist judge a lot lately."