Harassed journalist pursuing dog (7)
I believe the answer is:
hounded
'harassed' is the definition.
(I've seen this before)
'journalist pursuing dog' is the wordplay.
'journalist' becomes 'ed' (short for editor).
'pursuing' means one lot of letters go next to another.
'dog' becomes 'hound' (hound is a type of dog).
'ed' put after 'hound' is 'HOUNDED'.
(Other definitions for hounded that I've seen before include "Badgered" , "Dogged" , "harassed" .)