Stomach ringer, Yankee (5)
I believe the answer is:
belly
'stomach' is the definition.
(I know that stomach can be written as belly)
'ringer yankee' is the wordplay.
'ringer' becomes 'bell' (a bell rings).
'yankee' becomes 'Y' (phonetic alphabet: alpha, bravo, charlie etc.).
'bell'+'y'='BELLY'
(Other definitions for belly that I've seen before include "Abdomen" , "Paunch" , "Stomach" , "Corporation" , "Tummy" .)