antagonist

Term: antagonist

Literally meaning: “against fighter”

Origin: Anc Greek

ανταγωνιστής/antagonistis(= competitor, opponent, enemy) >αντί-/anti- (=prefix meaning opposed to, against, instead) + αγωνιστής/agonistis(=fighter, combatant) > αγών/agon(=contest, fight)

Coined/History 

(?)

Definition

1. (pharmacology) Antagonist is a chemical substance  that  binds to a neuronal receptor inhibiting the sugnal triggered by an agonist (stimulator of receptor). E.g heroin overdose is usually treated with an opiod anatagonist, such as naloxone
2. (microbiology) An antagonist is an organism that competes  another organism by the production of antibiotis or lytic enzymes.