Hog left to have a gawp (4)
I believe the answer is:
ogle
'a gawp' is the definition.
(I've seen this before)
'hog left to have' is the wordplay.
'to have' indicates the answer is hidden within the clue.
'OGLE' can be found hidden inside 'hog left'.
(Other definitions for ogle that I've seen before include "Lasciviously look" , "Perv" , "Amorous glance" , "Stare lewdly" , "Cast lascivious glances" .)