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

Patients treated with semaglutide had a 46 percent lower risk of developing ADRD than those receiving insulin, a 33 percent lower risk than those on metformin, and a 20 percent lower risk than those on earlier GLP-1 agonists. —Jenna Sundel, MSNBC Newsweek, 25 June 2025

For a long time, dopamine agonists were the first line of medications. —Madeline Holcombe, CNN Money, 11 June 2025

In May 2024, a KFF Health Tracking Poll found that approximately 6 percent of American adults—about 15 million people—were using GLP-1 agonists such as Ozempic, either for diabetes treatment or weight loss. —Isabel Van Brugen, MSNBC Newsweek, 5 June 2025

Between 2010 and 2018, half of the participants took GLP-1 receptor agonists (GLP-1 RAs) — injectable medications for obesity and type 2 diabetes — with at least six drug purchases within 12 months. —Melissa Rudy, FOXNews.com, 14 May 2025

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