Stop loan, wasting pound (3)
I believe the answer is:
end
'stop' is the definition.
(synonyms)
'loan wasting pound' is the wordplay.
'loan' becomes 'lend' (synonyms).
'wasting' indicates named letters should be taken away.
'pound' becomes 'L' (the pound sign is based on an L).
'lend' with 'l' taken out is 'END'.
(Other definitions for end that I've seen before include "'Conclusion, finale (3)'" , "For Chelsea or Villa, it's a" , "Exterminate - object" , "Unyielding" , "Completion" .)