gadfly

Meaning

Noun

• Any dipterous insect of the family Oestridae, commonly known as botflies.
• A horsefly: any of various species of fly, of the family Tabanidae, 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.
• A bloodsucker; a person who takes without giving back.

Origin

• From gad + fly.