Your antagonist is your opponent or enemy. Spassky had never previously lost to his antagonist. your opponent in a competition, battle, quarrel etc protagonist
A chemical that binds to a receptor and blocks it, producing no response, and preventing agonists from binding, or attaching, to the receptor Antagonists include caffeine and naloxone
One agent that opposes or fights the action of another For example, insulin lowers the level of glucose (sugar) in the blood, whereas glucagon raises it; therefore, insulin and glucagon are antagonists
In fiction, the main character who comes into conflict with the protagonist (hero or heroine) The antagonist could, in some stories, be a thing or situation (a monster, a storm, a flood, etc )
A drug or a compound that opposes the physiological effects of another At the receptor level, it is a chemical entity that opposes the receptor- associated responses normally induced by another bioactive agent [IUPAC Medicinal Chemistry] Compare agonist
A substance that tends to nullify the action of another; in pharmaceutical terms, a drug that binds to a receptor without eliciting a biological response
Describes the function of the medication at its target site Drugs function by effectively reducing the number of receptors available for the transmitter to activate, thus trying to reestablish normal physiological function or prevent a disease from occurring An antagonist will bind to a receptor site but will not cause any change in the function of the receptor or the cell They will prevent the agonist compound from having any effect on the cell
 In fiction, the main character who comes into conflict with the protagonist (hero or heroine)  The antagonist could, in some stories, be a thing or situation (a monster, a storm, a flood, etc )
The character, force, or collection of forces in fiction or drama that opposes the protagonist and gives rise to the conflict of the story; an opponent of the protagonist, such as Claudius in Shakespeares play Hamlet See also character, conflict
a drug that neutralizes or counteracts the effects of another drug a muscle that relaxes while another contracts; "when bending the elbow the triceps are the antagonist