One who antagonizes or stirs.
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.
Something or someone displeasing; anything that is disagreeable.
Causing repugnance; unpleasant to the feelings or senses; displeasing.