Moderated rage displayed by top journalist (8)
I believe the answer is:
tempered
'moderated' is the definition.
('temper' can be a synonym of 'moderate')
'rage displayed by top journalist' is the wordplay.
'rage' becomes 'temper' (temper means anger or rage).
'displayed by' is a charade indicator (letters next to each other).
'top journalist' becomes 'ed' (short for editor).
'temper'+'ed'='TEMPERED'
(Other definitions for tempered that I've seen before include "Strengthened" , "watered down" , "Neutralised, counterbalanced" , "Heat-treated" , "Made hard through heating and cooling" .)