Dog botherer (4)
I believe the answer is:
flea
'dog botherer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for flea that I've seen before include "beastie?" , "little pest" , "Small jumper in small circus" , "Tiny circus performer?" , "In one's ear, it's a stinging rebuke" .)