agonist

noun

ag·​o·​nist ˈa-gə-nist How to pronounce agonist (audio)
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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The findings come at a time when prescription weight loss medications, particularly GLP-1 receptor agonists, are gaining in popularity. — Khloe Quill, FOXNews.com, 13 Oct. 2026 Its structure puts it into a completely separate class of synthetic opioid agonists, though, one that preclinical studies suggest may affect breathing and blood flow at far lower doses than even fentanyl. — New Atlas, 30 Sep. 2026 Existing glucagonlike peptide 1 (GLP-1) receptor agonist drugs such as semaglutide, sold as Ozempic and Wegovy, bind to GLP-1 hormone receptors in the brain, where the receptors help regulate hunger. — Jackie Flynn Mogensen, Scientific American, 29 Sep. 2026 The Danish drugmaker has licensed from Hengrui Pharma a once-weekly, oral GLP-1/GIP receptor agonist that is ready for Phase 1 clinical development. — Meghana Keshavan, STAT, 29 Sep. 2026 See All Example Sentences for agonist

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

Time Traveler
The first known use of agonist was in 1658

Rhymes for agonist

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Browse Nearby Words

agonise
agonist
agonistic
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Cite this Entry

“Agonist.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/agonist. Accessed 20 Oct. 2026.

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Medical Definition

agonist

noun
ag·​o·​nist ˈag-ə-nəst How to pronounce agonist (audio)
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

More from Merriam-Webster on agonist

Britannica.com: Encyclopedia article about agonist

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