Unrestrained nude about to show stomach (6)
I believe the answer is:
endure
'stomach' is the definition.
('endure' can be a synonym of 'stomach')
'unrestrained nude about' is the wordplay.
'unrestrained' indicates anagramming the letters.
'about' becomes 're' (regarding**).
'nude' with letters rearranged gives 'endu'.
'endu'+'re'='ENDURE'
'to show' is the link.
(Other definitions for endure that I've seen before include "Go through" , "Undergo a tough time" , "Suffer, tolerate" , "Remain in existence; suffer" , "survive" .)