Better church line supporting European vote (5)
I believe the answer is:
excel
'better' is the definition.
(thesaurus)
'church line supporting european vote' is the wordplay.
'church' becomes 'ce' (abbreviation for Church of England).
'line' becomes 'l'.
'supporting' says to put letters next to each other (in a down clue, some letters go below others).
'european' becomes 'e' (abbreviation e.g. EU).
'vote' becomes 'x' (how votes are marked).
'ce'+'l'='cel'
'e'+'x'='ex'
'cel' put after 'ex' is 'EXCEL'.
(Other definitions for excel that I've seen before include "Do particularly well" , "Do exceedingly well" , "Surpass; shine" , "well above average" , "Do really well, outshine others" .)