gadfly

noun

Etymology: From gad (“sharp point, spike; (dialectal) sharp-pointed rod for driving cattle, horses, etc., goad”) + fly, in the sense of a fly which irritates cattle, etc., by biting them, similar to the prodding of a goad. Gad is derived from Middle English gad, gadde (“metal spike with a sharp point; stick with a sharp point for driving animals, goad; metal bar or rod, ingot; (by extension) lump of material; metal rod for measuring land; (by extension) unit of linear measure equal to about 10 to 16 feet”), borrowed from Old Norse gaddr (“spike; goad”), from Proto-Germanic *gazdaz (“spike; goad”), further etymology uncertain. Sense 2.1.1 (“person who upsets the status quo”) may allude to the Apology by the Greek philosopher Plato (428/427 or 424/423 – 348/347 B.C.E.), where he describes Socrates (c. 470 – 399 B.C.E.) acting as a goad to the Athenian political scene like a gadfly (Ancient Greek μῠ́ωψ (mŭ́ōps)) arousing a sluggish horse.

1. Any dipterous (“two-winged”) insect or fly of the family Oestridae (commonly known as a botfly) or Tabanidae (horsefly), noted for irritating animals by buzzing about them, and biting them to suck their blood; a gadbee.

   “He that made that ryme in jeſt, little conſidered what a gad-fly may doe in earneſt. It is ſmall wiſedome to contemne the ſmalleſt enemy; the gad-fly is a little creature, but ſome little creatures be ſtingers; […]”

   “Light fly his ſlumbers, if perchance a flight / Of angry gad-flies faſten on the herd; […]”

2. A person or thing that irritates or instigates.

   “VVhat gad flye tickles ſo this Macrinus, / That vp-flinging thy tayle, he breakes thus from me.”

3. A person or thing that irritates or instigates.

   “There is a function for the gadfly who poses questions that many specialists would like to overlook. Polemics is healthy.”

   “What was required now was the intervention of some men who were not gadflies. […] The logic of [Charles] Pearson's arguments was accepted, up to a point, by a consortium of businessmen. In August 1854, […] the consortium obtained royal assent for […] the Metropolitan Railway. […] In 1859, when it looked as though the Metropolitan Railway Company would be wound up with no line built, he [Pearson] wrote a pamphlet: A Twenty Minutes Letter to the Citizens of London in Favour of the Metropolitan Railway and City Station. Gadfly he may have been, but by this 'letter' he persuaded the Corporation of London to invest £200,000 in the line, a most unusual example of a public body investing in a Victorian railway.”

4. Synonym of gadabout (“a person who restlessly moves from place to place, seeking amusement or the companionship of others”).

   “VVhat VVinnie? VVife, I ſay? out of dores at this time! vvhere ſhould I ſeeke the Gad-flye?”

   “VVhere are thoſe gad-flies going? to ſome Junket novv; […]”

5. A person who takes without giving back; a bloodsucker.

   “He’s a regular gadfly and takes advantage of his friend’s generosity.”