Endless wretchedness for Scrooge (5)
I believe the answer is:
miser
'scrooge' is the definition.
('miser' can be a synonym of 'scrooge')
'endless wretchedness' is the wordplay.
'endless' means to remove the last letter.
'wretchedness' becomes 'misery' ('misery' can be a synonym of 'wretchedness').
'misery' with its final letter taken off is 'MISER'.
'for' acts as a link.
(Other definitions for miser that I've seen before include "One doesn't spend much" , "Wealth hoarder" , "Avaricious hoarder" , "Stingy hoarder" , "we may find boring" .)