Corpulent – kind of ale (5)
I believe the answer is:
stout
I believe this clue is a double definition.
'corpulent' is the first definition.
(I've seen this before)
'kind of ale' is the second definition.
(I know that stout is a type of ale)
(Other definitions for stout that I've seen before include "Overweight; porter" , "Rather fat; determined" , "Beer with malt" , "Dark ale" , "Resolute" .)