Pronunciation: (prō-tag'u-nist),[key] —n. 1. the leading character, hero, or heroine of a drama or other literary work.
2. a proponent for or advocate of a political cause, social program, etc.
3. the leader or principal person in a movement, cause, etc.
4. the first actor in ancient Greek drama, who played not only the main role, but also other roles when the main character was offstage. Cf. deuteragonist, tritagonist. 5. Physiol.agonist.