There's nothing in watering-hole for wild swine (4)
I believe the answer is:
boar
'wild swine' is the definition.
(I've seen this in another clue)
'there's nothing in watering-hole' is the wordplay.
'there's nothing' becomes 'o' (I've seen this in other clues).
'in' indicates putting letters inside.
'watering hole' becomes 'bar' (I've seen this in another clue).
'o' placed into 'bar' is 'BOAR'.
'for' acts as a link.
(Other definitions for boar that I've seen before include "Wild pig sounds tedious" , "Wild animal, sounds like drill" , "The head for drink Falstaff had" , "Resting place for birds or bats" , "Uncastrated male pig" .)