An opponent or enemy.
A muscle that acts in opposition to another.
A chemical that binds to a receptor but does not produce a physiological response, blocking the action of agonist chemicals.
The main character or force opposing the protagonist in a literary work or drama.
One who antagonizes or stirs.
A member of a confederacy.
An accomplice in a plot.
An actor who participates in a psychological experiment pretending to be a subject but in actuality working for the researcher.
of, relating to, or united in a confederacy
banded together; allied.
To combine in a confederacy.