Corpulent porter (5)
I believe the answer is:
stout
I believe this clue is a double definition.
'corpulent' is the first definition.
(thesaurus)
'porter' is the second definition.
('stout' can be a synonym of 'porter')
(Other definitions for stout that I've seen before include "Thick; beer" , "Corpulent" , "Round" , "Kind of beer" , "Portly or stalwart" .)