Dealt with traditional journalist (6)
I believe the answer is:
traded
'dealt' is the definition.
(I've seen this before)
'with traditional journalist' is the wordplay.
'with' means one lot of letters go next to another.
'traditional' becomes 'trad' (abbreviation - especially in music 'trad jazz').
'journalist' becomes 'ed' (short for editor).
'trad' put next to 'ed' is 'TRADED'.
(Other definitions for traded that I've seen before include "Darted (anag.)" , "Did business, bought and sold" , "Bought and sold goods" , "Bought and sold for profit" , "Engaged in commerce" .)