Impeccable European Republicans with various roles succeeded (9)
I believe the answer is:
errorless
'impeccable' is the definition.
(thesaurus)
'european republicans with various roles succeeded' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'republicans' becomes 'RR' (two abbreviations for Republican).
'with' is a charade indicator (letters next to each other).
'various' is an anagram indicator.
'succeeded' becomes 's' (genealogical abbreviation).
'roles' with letters rearranged gives 'orles'.
'e'+'rr'+'orles'+'s'='ERRORLESS'
(Other definitions for errorless that I've seen before include "Perfect" , "Correct" .)