Amateur obviously concealing currency (4)
I believe the answer is:
euro
'currency' is the definition.
(currency of the Eurozone)
'amateur obviously concealing' is the wordplay.
'concealing' indicates a hidden word.
'EURO' is hidden in the letters of 'amateur obviously'.
(Other definitions for euro that I've seen before include "Continental purchaser" , "France's unit of currency" , "Multi-national currency" , "Currency of France" , "Large kangaroo" .)