Preoccupied bosses confused by journalist (8)
I believe the answer is:
obsessed
'preoccupied' is the definition.
(obsessing is a kind of preoccupying)
'bosses confused by journalist' is the wordplay.
'confused' indicates anagramming the letters.
'by' says to put letters next to each other.
'journalist' becomes 'ed' (short for editor).
'bosses' with letters rearranged gives 'obsess'.
'obsess'+'ed'='OBSESSED'
(Other definitions for obsessed that I've seen before include "Being excessively concerned with something" , "with bee in her bonnet?" , "Showing excessive or compulsive concern with something" , "With mind continually occupied, abnormally focused" , "Compulsively concerned with something" .)