Corpulent, plump (6)
I believe the answer is:
rotund
I believe this clue is a double definition.
'corpulent' is the first definition.
(I know that corpulent can be written as rotund)
'plump' is the second definition.
(I've seen this before)
(Other definitions for rotund that I've seen before include "Bulging" , "Round and plump" , "Full" , "'Corpulent, round (6)'" , "Portly" .)