What Does Antagonist Mean?

Its means that someone is working against the protagonist.

The word antagonist is simply an antonymous term for protagonist and the antagonist acts exactly in opposite of what the hero or the protagonist does.
The term can be applied to anybody whether it is a person or an institution but the motive is always the same. In fictional stories it can be described as a destructive force and the fight must go on till the hero thrashes the villain that is the antagonist.

There is no definition that can clearly define the destructive force or the constructive force but as the story progresses the heroic and villainous traits of characters evolve and it get divided into the protagonist and the antagonist. Some times you can find the antagonistic or protagonist qualities in the same character and is decided only by the acts which he does at some point of time.

Noun Singular
antagonist
Plural
antagonists


antagonist (plural antagonists)

An opponent or enemy.
One who antagonizes or stirs.
(biochemistry) A chemical that binds to a receptor but does not produce a physiological response, blocking the action of agonist chemicals.

The main character opposing the protagonist in a literary work or drama