Kite stabilizer (4)
I believe the answer is:
'kite stabilizer' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tail that I've seen before include "Flexible part that extends from an animal's rear" , "Comet's luminous trail" , "Dog - or part of one" , "Follow; end part" , "Follow -- rear end" .)