Achievement of one's supporters, you might say (4)
I believe the answer is:
feat
'achievement' is the definition.
(I know that feat is a type of achievement)
'one's supporters you might say' is the wordplay.
'one's supporters' becomes 'feet' (your feet support your body).
'you might say' shows a homophone (sound like).
'feet' sounds like 'FEAT'.
'of' is the link.
(Other definitions for feat that I've seen before include "Exploit; achievement" , "Notable achievement" , "Remarkable achievement of fate" , "Great deed" , "Achievement needing great courage or skill" .)