Restricted group shut down retail outlet (6,4)
I believe the answer is:
closed shop
'restricted group' is the definition.
The answer and definition can be both groups as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'shut down retail outlet' is the wordplay.
'shut down' becomes 'closed' (synonyms).
'retail outlet' becomes 'shop' (I've seen this before).
'closed'+'shop'='CLOSED SHOP'
Can you help me to learn more?
(Other definitions for closed shop that I've seen before include "where union holds sway" , "Exclusive workers" , "Ceased trading" , "factory where all the workers are unionists" , "firm with restrictive hiring policy" .)