[{"Bold_text": "noun", "List Items": ["a person engaged in a contest, conflict, struggle, etc., especially the protagonist a literary work.", "a person who is torn by inner conflict.", "Physiology.a contracting muscle whose action is opposed by another muscle.Compare antagonist(def3) antagonist(def3).", "Pharmacology.a chemical substance capable of activating a receptor to induce a full or partial pharmacological response.Compare antagonist(def5) antagonist(def5)."]}]