Crossword Genius

Livestock-biting insect whose name may be used to refer to an annoying person (6)

Ross

I believe the answer is:

gadfly

(Other definitions for gadfly that I've seen before include "Persistently annoying person" , "persistent irritant" , "Persistently annoying insect" , "provocative pest" , "Bloodsucker; annoying person" .)

I've seen this clue in The Times.
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