any of various flies such as a horsefly, botfly, or warble fly that bite or annoy livestock.
fly that bites livestock
In literal use, gadfly refers to any of various flies (such as a horsefly, botfly, or warble fly) that bite or annoy livestock. Gadfly is most popular in figurative use, however, where it refers to someone who provokes or annoys other people especially by persistent criticism.
