A barrier to a dodgy dealer (5)
I believe the answer is:
fence
I believe this is a double definition.
'a barrier' is the first definition.
(I know that fence is a type of barrier)
'dodgy dealer' is the second definition.
(trader of stolen goods)
'to a' is the link.
(Other definitions for fence that I've seen before include "Stolen goods dealer" , "Enclosing barrier" , "crook" , "Dealer in stolen property" , "Receiver of stolen goods" .)