Rehearsed a script translated by the editor (9)
I believe the answer is:
practised
'rehearsed' is the definition.
('practise' can be a synonym of 'rehearse')
'a script translated by the editor' is the wordplay.
'translated' indicates an anagram.
'by' says to put letters next to each other.
'the editor' becomes 'ed' (abbreviation).
'a'+'script'='ascript'
'ascript' with letters rearranged gives 'practis'.
'practis'+'ed'='PRACTISED'
(Other definitions for practised that I've seen before include "Expert" , "Learned by repetition" , "Carried out or rehearsed" .)