Hog left to have a look (4)
I believe the answer is:
ogle
'a look' is the definition.
(I know this)
'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 "Eye lustfully" , "Amorous glance" , "Make eyes at" , "Cast amorous glances" , "Lasciviously look" .)