Keep an eye on hunter? (5)
I believe the answer is:
watch
I believe this is a double definition.
'keep an eye on' is the first definition.
('watch' can be a synonym of 'keep an eye on')
'hunter?' is the second definition.
(hunter is a kind of watch)
(Other definitions for watch that I've seen before include "Keep an eye on - timepiece" , "period of duty" , "View" , "Timepiece - look out" , "Observe - timepiece" .)