Drain away money (5)
I believe the answer is:
dinar
'money' is the definition.
(I know that dinar is a currency)
'drain away' is the wordplay.
'away' indicates an anagram (letters move away from their original places).
'drain' is an anagram of 'DINAR'.
(Other definitions for dinar that I've seen before include "Unit of currency in former Yugoslavia and other Middle East countries" , "currency from abroad" , "Currency of several Arab countries" , "Monetary unit of Algeria" , "money" .)