An antagonist refers to a character, force, or entity that opposes the protagonist or the main character in a story. Synonyms for this concept including adversary, enemy, foe, and competitor. Other synonyms for antagonist are opponent, rival, nemesis, and antagonist. These words all refer to someone or something that stands in the way of the protagonist, creating tension and conflict in the story. Other related words that can be used as synonyms for antagonist include villain, antagonist, and antagonist. Overall, these words all capture the idea of a force that creates opposition or resistance to the protagonist in a story.