Bother old horse (3)

I believe the answer is:

nag

I believe this clue is a double definition.

'bother' is the first definition.
(I've seen this before)

'old horse' is the second definition.
(a nag is an old horse)

(Other definitions for nag that I've seen before include "Bother persistently" , "Pester; old horse" , "Scold like an old horse" , "Ailing horse" , "Henpeck, scold non-stop" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app