Definitions for gadflyˈgædˌflaɪ
Random House Webster's College Dictionary
any of various flies, as a horsefly or warble fly, that bite or annoy livestock.
a person who persistently annoys or stirs up others, esp. with provocative criticism.
Origin of gadfly:
pest, blighter, cuss, pesterer, gadfly(noun)
a persistently annoying person
any of various large flies that annoy livestock
Any dipterous insect of the genus Oestrus, and allied group of botflies.
A horsefly: any of various species of fly, of the family Tabanid[ae], noted for buzzing about animals and sucking their blood.
One who upsets the status quo by posing upsetting or novel questions, or attempts to stimulate innovation by proving an irritant.
One who merely irritates without making useful suggestions.
He's a regular gadfly and takes advantage of his friend's generosity.
Origin: "fly which bites cattle", from gaddr.
any dipterous insect of the genus Oestrus, and allied genera of botflies