Drain off money (5)
I believe the answer is:
dinar
'money' is the definition.
(I know that dinar is a currency)
'drain off' is the wordplay.
'off' indicates an anagram.
'drain' with letters rearranged gives 'DINAR'.
(Other definitions for dinar that I've seen before include "Currency of several Arab states" , "Iraqi CURRENCY" , "money" , "Monetary unit of Algeria" , "currency from abroad" .)