An antagonist is a group of characters, institution, or concept that stands in or represents opposition against which the protagonist(s) must contend. In other words, an antagonist is a person or a group of people who opposes a protagonist.
The English word antagonist comes from the Greek ἀνταγωνιστής - antagonistēs , "opponent, competitor, enemy, rival," which is derived from anti-("against") and agonizesthai ("to contend for a prize").
In the classic style of stories where the action consists of a hero fighting a villain/enemy, the two may be regarded as protagonist and antagonist, respectively. However, the villain of the story is not always the same as the antagonist, as some narratives cast the villain in the protagonist role, with the opposing hero as the antagonist.
An antagonist also may represent a threat or obstacle to the main character by its existence and not necessarily targeting him or her in a deliberate manner.
Examples in both film and theater include Sauron, the main antagonist in The Lord of the Rings, who constantly battles the series' protagonists, and Tybalt, an antagonist in Romeo and Juliet, who slays Mercutio and whose later death results in the exiling of one of the play's protagonists, Romeo. In stories, a convention of antagonists is that their moral choices are less savory than those of protagonists. This is often used by an author to create conflict within a story. However, this is merely a convention, and the reversal of this can be seen in the character Macduff from Macbeth, who is arguably morally correct in his desire to fight the tyrant Macbeth. An anime and light novel example would be Akihiko Kayaba from Sword Art Online, who is disguised as the leader of the Knights of Blood, Heathcliff.
Antagonist is an American metalcore band from Whittier, California, formed in 1998. They released numerous EPs prior to being signed with Prosthetic Records. They have released two albums while under the Prosthetic Records banner, "Exist" and "World in Decline".
The current line-up of the band consists of Carlos Garcia (lead guitar/vocals), Nick Reyes (bass/backing vocals), Roland Leonard (lead guitar/backing vocals) and Orlando "Lond" Garcia (drums).
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens agonist-mediated responses rather than provoking a biological response itself upon binding to a receptor. They are sometimes called blockers; examples include alpha blockers, beta blockers, and calcium channel blockers. In pharmacology, antagonists have affinity but no efficacy for their cognate receptors, and binding will disrupt the interaction and inhibit the function of an agonist or inverse agonist at receptors. Antagonists mediate their effects by binding to the active (orthosteric = right place) site or to allosteric (= other place) sites on receptors, or they may interact at unique binding sites not normally involved in the biological regulation of the receptor's activity. Antagonist activity may be reversible or irreversible depending on the longevity of the antagonist–receptor complex, which, in turn, depends on the nature of antagonist–receptor binding. The majority of drug antagonists achieve their potency by competing with endogenous ligands or substrates at structurally defined binding sites on receptors.
You crossed your fingers when you said forever
I should have pulled the trigger
You look much better smashed into the ground
I hope I'm not a fortune teller
DEATH IS SERENITY
Open your eyes for one last sunset
I'll never have an explanation for your utterly pathetic
attempt at love