Clothes are not finished in Great Britain (4)
I believe the answer is:
garb
'clothes' is the definition.
(garb is a kind of clothes)
'are not finished in great britain' is the wordplay.
'not finished' means to remove the last letter.
'in' means one lot of letters goes inside another.
'great britain' becomes 'gb'.
'are' with its last letter taken off is 'ar'.
'ar' placed within 'gb' is 'GARB'.
(Other definitions for garb that I've seen before include "gear discovered" , "Style of clothing" , "Outfit" , "Fashion of dress" , "Dress - clothing" .)