Drain away money (5)
I believe the answer is:
dinar
'money' is the definition.
(I've seen this before)
'drain away' is the wordplay.
'away' indicates anagramming the letters (letters move away from their original places).
'drain' anagrammed gives '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" .)