US general stores overwhelm exhausted shopper (8)
I believe the answer is:
customer
'shopper' is the definition.
(thesaurus)
'us general stores overwhelm exhausted' is the wordplay.
'us general' becomes 'Custer' (George Custer, 19th-century US cavalry commander).
'stores' is an insertion indicator.
'exhausted' suggests removing the centre (the word is emptied out or exhausted).
'overwhelm' with its centre taken out is 'om'.
'custer' placed around 'om' is 'CUSTOMER'.
(Other definitions for customer that I've seen before include "Person shopping" , "Someone shopping" , "Rail passenger, nowadays" , "The person who is said in business to be always right" , "The one who pays is always right" .)