Bishop without polish (8)
I believe the answer is:
blacking
'polish' is the definition.
(I know that blacking is a type of polish)
'bishop without' is the wordplay.
'bishop' becomes 'B' (abbreviation for bishop in chess).
'without' becomes 'lacking' (I've seen this in another clue).
'b'+'lacking'='BLACKING'
(Other definitions for blacking that I've seen before include "Refusing to handle" , "polish" .)