Without polish, without lead (7)
I believe the answer is:
lacking
'without' is the definition.
(I've seen this in another clue)
'polish without lead' is the wordplay.
'polish' becomes 'blacking' (blacking is a kind of polish).
'without lead' means to remove the first letter.
'blacking' with its first letter removed is 'LACKING'.
(Other definitions for lacking that I've seen before include "Absent, deficient" , "'Deficient, wanting (7)'" , "Deficient or inadequate" , "Short" , "Being without, wanting" .)