Reread EP Thompson? Some of it’s brilliant (5)
I believe the answer is:
adept
'it's brilliant' is the definition.
(thesaurus)
'reread ep thompson? some' is the wordplay.
'some' says the answer is hidden in the clue.
'ADEPT' is hidden within 'reread ep thompson'.
'of' is the link.
(Other definitions for adept that I've seen before include "Skillful" , "Completely skilled" , "capable" , "One very skilled at work" , "Skilful and adroit" .)