Dated scoundrel with hand missing and a slippery customer (4)
I believe the answer is:
heel
'dated scoundrel' is the definition.
(dated term for a scoundrel)
'hand missing and a slippery customer' is the wordplay.
'missing' is a deletion indicator.
'a slippery customer' becomes 'eel'.
'hand' with 'and' taken out is 'h'.
'h'+'eel'='HEEL'
'with' is the link.
(Other definitions for heel that I've seen before include "afoot?" , "one regarded with contempt" , "Bounder; part of foot" , "knob" , "Crusty end of a loaf" .)