gad·​fly ˈgad-ˌflī How to pronounce gadfly (audio)
: any of various flies (such as a horsefly, botfly, or warble fly) that bite or annoy livestock
: a person who stimulates or annoys other people especially by persistent criticism
a political gadfly

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The Gadfly of Athens

The history of gadfly starts with gad, which now means "chisel" but which formerly could designate a spike, spear, or rod for goading cattle. Late in the 16th century, gad was joined with fly to designate any of several insects that aggravate livestock. Before too long, we began applying gadfly to people who annoy or provoke others. One of history's most famous gadflies was the philosopher Socrates, who was known for his constant questioning of his fellow Athenians' ethics, misconceptions, and assumptions. In his Apology, Plato describes Socrates' characterization of Athens as a large and sluggish horse and of Socrates himself as the fly that bites and rouses it. Many translations use gadfly in this portion of the Apology, and Socrates is sometimes referred to as the "gadfly of Athens."

Examples of gadfly in a Sentence

the journalist was known as a gadfly for exposing hypocrisy in politics
Recent Examples on the Web Best Picture Down Rustin The Netflix biopic, which starts its brief theatrical run this week, is being celebrated for Colman Domingo’s performance as the openly gay gadfly who organized the March on Washington. Vulture, 3 Nov. 2023 Around them buzzes a motley chorus of hapless government agents, spies, and literary gadflies like Frankenstein author Mary Shelley and Lord Byron, who in his attempts to defend the Luddites in the halls of power, spends a lot of time getting twisted up in his own poetry. WIRED, 22 Oct. 2023 The same went for Bill Maher, HBO’s late-night gadfly (and a WGA member). Mikey O'Connell, The Hollywood Reporter, 25 Sep. 2023 After Donald Trump had blasted open Clinton’s blue wall and swept Michigan, Wisconsin, and Pennsylvania, Sanders could no longer be dismissed as a relic or a gadfly. Ross Barkan, The New Republic, 3 Aug. 2023 If a significant political figure (or even a compelling gadfly) runs in the primaries, then the incumbent is effectively doomed in November or beforehand. Walter Shapiro, The New Republic, 3 Apr. 2023 For Musk — a serial entrepreneur, controversy-stirring celebrity, terminally online gadfly and the richest man in the world by some counts — abruptly tapping the brakes on a $44-billion tech acquisition with a vague tweet is, well, just another Friday. Brian Contreras, Los Angeles Times, 13 May 2022 Despite Leguizamo’s best efforts, Rob is the most useless of them, mostly serving as a gadfly to his overburdened wife and constantly criticizing her lack of work-life balance. Joshua Alston, Variety, 30 Mar. 2023 Kennedy is an environmental attorney who more recently has gained notoriety as an anti-vaccine political gadfly. Dan Nowicki, The Arizona Republic, 8 May 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'gadfly.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


gad entry 1 + fly entry 4

First Known Use

1569, in the meaning defined at sense 1

Time Traveler
The first known use of gadfly was in 1569


Dictionary Entries Near gadfly

Cite this Entry

“Gadfly.” Dictionary, Merriam-Webster, Accessed 4 Dec. 2023.

Kids Definition


gad·​fly ˈgad-ˌflī How to pronounce gadfly (audio)
: any of various flies (as a horsefly or botfly) that are pests especially of livestock
: a person who annoys others especially by persistent criticism

Medical Definition


gad·​fly ˈgad-ˌflī How to pronounce gadfly (audio)
plural gadflies
: any of various flies (as a horsefly, botfly, or warble fly) that bite or annoy livestock

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