Describe number a bishop polished off (7)
I believe the answer is:
narrate
'describe' is the definition.
(thesaurus)
'number a bishop polished off' is the wordplay.
'number' becomes 'n'.
'bishop' becomes 'rr' (abbreviation for Right Reverend).
'polished off' becomes 'ate' (I've seen this in other clues).
'n'+'a'+'rr'+'ate'='NARRATE'
(Other definitions for narrate that I've seen before include "Tell the tale." , "Report; tell" , "tell tales" , "Relay" , "Give a spoken account" .)