agonist

noun ag·o·nist \ˈa-gə-nist\

Definition of AGONIST

: one that is engaged in a struggle

[from antagonist]

a : a muscle that is controlled by the action of an antagonist with which it is paired

b : a chemical substance capable of combining with a specific receptor on a cell and initiating the same reaction or activity typically produced by the binding endogenous substance <dopaminergic agonists> — compare antagonist 2b

Origin of AGONIST

Late Latin agonista competitor, from Greek agōnistēs, from agōnizesthai to contend, from agōn

First Known Use: circa 1623

Medical Dictionary

agonist

noun ag·o·nist \ˈag-ə-nəst\

Medical Definition of AGONIST

: a muscle that on contracting is automatically checked and controlled by the opposing simultaneous contraction of another muscle—called also agonist muscle, prime mover; compare antagonist a, synergist 2

: a chemical substance (as a drug) capable of combining with a receptor on a cell and initiating the same reaction or activity typically produced by the binding of an endogenous substance <binding of adrenergic agonists>—compare antagonist b