From Old English 'gād' (goad/spike) + fly — a biting insect that stings cattle into motion, famously adopted by Socrates as his self-description.
A fly that bites livestock; a person who provokes or annoys others, especially by persistent criticism.
From Old English 'gād' (goad, pointed stick) + 'fly.' A gadfly is a 'goad-fly' — an insect that stings cattle into motion, like a pointed stick. Socrates called himself the gadfly of Athens, stinging the lazy horse of the state into wakefulness. Key roots: gād (Old English: "goad, spike, pointed stick").
Socrates compared himself to a gadfly — and was executed for it. In Plato's Apology, Socrates says Athens is a 'great and noble horse which is rather sluggish owing to its size and needs to be stirred into life,' and he is the gadfly that stings it awake. The jury sentenced him to death. The word perfectly captures the paradox