Security is brought back in the store (7)
I believe the answer is:
deposit
'security' is the definition.
(I know that deposit is a type of security)
'is brought back in the store' is the wordplay.
'brought back' shows that the letters should be reversed in order.
'in the' indicates putting letters inside.
'store' becomes 'depot' (depot can mean a store or warehouse).
'is' reversed gives 'si'.
'si' inserted within 'depot' is 'DEPOSIT'.
(Other definitions for deposit that I've seen before include "Drop" , "Posited as down payment" , "Precipitate" , "Sediment or bank lodgment" , "Returnable sum" .)