noun, plural gad·flies.

any of various flies, as a stable fly or warble fly, that bite or annoy domestic animals.
a person who persistently annoys or provokes others with criticism, schemes, ideas, demands, requests, etc.

Origin of gadfly

First recorded in 1585–95; gad2 + fly2 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for gadfly

Contemporary Examples of gadfly

Historical Examples of gadfly

  • His efforts can only be compared with those of a gadfly or a mosquito.

  • The gadfly uses a like forethought in selecting a place for her eggs.

  • Some gadfly stings him: he seizes his tomahawk and is off on the trail.

    Obiter Dicta

    Augustine Birrell

  • She understood that he had invented a pretext in order to leave her alone with the Gadfly.

    The Gadfly

    E. L. Voynich

  • Presently he heard the Gadfly move restlessly two or three times.

    The Gadfly

    E. L. Voynich

British Dictionary definitions for gadfly


noun plural -flies

any of various large dipterous flies, esp the horsefly, that annoy livestock by sucking their blood
a constantly irritating or harassing person

Word Origin for gadfly

C16: from gad ² (sting) + fly ²
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for gadfly

1620s, "fly which bites cattle," probably from gad (n.) "goad, metal rod," here in the sense of "stinger;" but the sense is entangled with gad (v.) and another early meaning of gadfly was "someone who likes to go about, often stopping here and there" (1610s). Sense of "one who irritates another" is from 1640s (equivalent of Latin oestrus).

Online Etymology Dictionary, © 2010 Douglas Harper