noun
antagonist
an-TAG-uh-nist/ænˈtæɡənɪst/
A person or force that opposes the action of another.
The antagonist blocks the explorer's route through the guarded gate.

Etymology
An antagonist was someone who competed against another in battle or sport. The role broadened beyond those contests, giving the sense of an opponent who obstructs a central character or goal.
In context
betraying the main character in a Justified way however on the flip side of that the benefit of this antagonist archetype is that their betrayal can form a really interesting twist
More examples
- The novel gives its antagonist a believable motive.
- The substance acts as a receptor antagonist, blocking its activation.
- Two political antagonists debate the future of the project.
Forms
antagonist · antagonists
Similar words
- opponent
- The ordinary term for a person on the opposing side.
- inhibitor
- Specifically reduces an activity rather than opposing a person.