Barrier to a dodgy dealer (5)
I believe the answer is:
fence
This clue is a double definition.
'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 "Paling; criminal receiver" , "crook" , "Receiver of stolen goods" , "Railing" , "With blade, fight" .)