General appearance supermarket admits indefensible, initially (9)
I believe the answer is:
garibaldi
'general' is the definition.
(Giuseppe Garibaldi)
'appearance supermarket admits indefensible initially' is the wordplay.
'appearance' becomes 'garb'.
'supermarket' becomes 'aldi' (German supermarket also operating in the UK).
'admits' is an insertion indicator.
'initially' indicates taking the first letters.
The initial letter of 'indefensible' is 'i'.
'garb'+'aldi'='garbaldi'
'garbaldi' enclosing 'i' is 'GARIBALDI'.
(Other definitions for garibaldi that I've seen before include "military commander" , "Lady's blouse" , "Blouse; biscuit; Italian patriot" , "blouse, loose one" , "Italian leader; biscuit" .)