[{"Bold_text": "noun", "List Items": ["the leading character, hero, or heroine of a drama or other literary work.", "a proponent for or advocate of a political cause, social program, etc.", "the leader or principal person in a movement, cause, etc.", "the first actor in ancient Greek drama, who played not only the main role, but also other roles when the main character was offstage.Compare deuteragonist , tritagonist .", "Physiology. agonist ."]}]