agonist

noun

ag·​o·​nist ˈa-gə-nist 

1

: one that is engaged in a struggle

2

[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 sense 2b

Examples of agonist in a Sentence

Recent Examples on the Web

How GLP-1s May Affect Brain Health Analyses of large patient datasets have associated GLP-1 receptor agonists with a reduced risk of cognitive impairment and dementia. — Daniella Gray, MSNBC Newsweek, 10 Nov. 2026

Once inside the body, 7-OH, like mitragynine, is a partial agonist to the mu-opioid receptor. — Theresa Gaffney, STAT, 6 Nov. 2026

Novo is preparing to launch CagriSema, a combination of the GLP-1 receptor agonist semaglutide and the long-acting amylin analogue cagrilintide. — Elsa Ohlen, CNBC, 4 Nov. 2026

Testing the system in people with amputations The team tested the technique in three participants with below-knee amputations who had undergone an agonist-antagonist myoneural interface (AMI) procedure. — Kaif Shaikh, Interesting Engineering, 29 Oct. 2026

Word History

Etymology

borrowed from Late Latin agōnista, borrowed from Greek agōnistḗs, from agōnízesthai "to contend, fight" + -istēs -ist entry 1 — more at agonize

First Known Use

1658, in the meaning defined at sense 1

Rhymes for agonist

• antagonist
• protagonist

Medical Definition

agonist

noun

ag·​o·​nist ˈag-ə-nəst 

1

: 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 sense a, synergist sense 2

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 sense b