Fight a dealer in stolen goods (5)
I believe the answer is:
fence
I believe this clue is a double definition.
'fight' is the first definition.
(fencing is a sword-fighting sport)
'a dealer in stolen goods' is the second definition.
(I've seen this before)
(Other definitions for fence that I've seen before include "Fight with sword - barrier" , "Barrier; receiver" , "Shield" , "use offensive weapons" , "who deals in hot stuff" .)