Refuse to deal with (7)
I believe the answer is:
boycott
'refuse to deal with' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for boycott that I've seen before include "ex-Yorkshire cricket captain" , "Refuse to handle or deal with" , "send to Coventry" , "Refuse to deal with - outlaw" , "Refuse to buy or handle goods" .)