Moaned awfully about start of bloating in belly (7)
I believe the answer is:
abdomen
'belly' is the definition.
('abdomen' can be a synonym of 'belly')
'moaned awfully about start of bloating' is the wordplay.
'awfully' indicates anagramming the letters.
'about' means one lot of letters goes inside another.
'start of' indicates taking the first letters.
The initial letter of 'bloating' is 'b'.
'moaned' anagrammed gives 'adomen'.
'adomen' going around 'b' is 'ABDOMEN'.
'in' acts as a link.
(Other definitions for abdomen that I've seen before include "Tummy" , "Part of the body below chest and diaphragm" , "Midriff" , "Central region" , "Belly" .)