1. A person who actively opposes or is hostile to someone or something; an adversary
The antagonist in the novel seeks revenge against the protagonist.
O antagonista no romance busca vingança contra o protagonista.
2. In literature, film, or drama: a character in opposition to the main character (protagonist)
The villain is often the main antagonist of the story.
O vilão é frequentemente o antagonista principal da história.
3. In medicine/pharmacology: a substance that interferes with or inhibits the physiological action of another substance
The drug acts as an antagonist to the hormone receptors.
A droga atua como antagonista dos receptores de hormônio.