Repeated feature is a sign of corpulence (6,4)
I believe the answer is:
double chin
'sign of corpulence' is the definition.
'double chin' can be an answer for 'sign' (I have seen 'Sign of obesity' mean 'double chin' so perhaps 'sign' could also mean 'double chin'). I'm not certain of the 'of corpulence' bit.
'repeated feature' is the wordplay.
'repeated' becomes 'double' (I can't explain this - if you can you should believe this answer much more).
'feature' becomes 'chin' (facial feature).
'double'+'chin'='DOUBLE-CHIN'
'is a' acts as a link.
Can you help me to learn more?
(Other definitions for double chin that I've seen before include "Sign of obesity" , "Facial feature of chubbier persons" , "flabby feature" , "Unattractive feature" .)