Pig food (4)
I believe this is a double definition.
'pig' is the first definition.
(thesaurus)
'food' is the second definition.
(pork is a kind of food)
(Other definitions for pork that I've seen before include "Swine's flesh" , "Meat used in sausages" , "what we get from swine" , "Bacon, e.g." , "Meat used in chorizo" .)
'pig food' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for slop that I've seen before include "(Of liquid) spill over" , "Spilled liquid" , "overflow" , "Bobby" , "Splash" .)
'pig food' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for swill that I've seen before include "Wet feed for pigs" , "Refuse" , "Wet pig feed" , "Guzzle" , "Pigs' food" .)