Star and journalist sharply divided (9)
I believe the answer is:
polarised
'sharply divided' is the definition.
'star and journalist' is the wordplay.
'star' becomes 'polaris' (star within the constellation Ursa Minor).
'and' is a charade indicator (letters next to each other).
'journalist' becomes 'ed' (short for editor).
'polaris'+'ed'='POLARISED'
(Other definitions for polarised that I've seen before include "camps that are opposite?" , "Separate" , "in opposing camps" , "Extremely divided" , "like some light" .)