He's in jug (4)
I believe the answer is:
toby
This clue is a double definition.
'he's' is the first definition.
'jug' is the second definition.
(I've seen this in another clue)
'in' is the link.
(Other definitions for toby that I've seen before include "fellow" , "dog with frill round neck" , "Kind of jug" , "This Jug is like man with three-cornered hat" , "Belch, perhaps" .)