A bit cruel recasting Grease? (9)
I believe the answer is:
lubricate
'grease?' is the definition.
('lubricate' can be a synonym of 'grease')
'a bit cruel recasting' is the wordplay.
'recasting' indicates an anagram.
'a'+'bit'+'cruel'='abitcruel'
'abitcruel' is an anagram of 'LUBRICATE'.
(Other definitions for lubricate that I've seen before include "supply with booze" , "Bribe" , "Apply oil/grease" , "Oil (a mechanism)" , "Apply oil or grease to" .)