Horse; watch (6)
I believe the answer is:
hunter
I believe this clue is a double definition.
'horse' is the first definition.
(I've seen this before)
'watch' is the second definition.
(type of watch)
(Other definitions for hunter that I've seen before include "Pursuer of game" , "Orion -- pocket watch with a hinged protective lid" , "'Nimrod or Orion, say (6)'" , "someone on safari" , "one chasing the game?" .)