Some connoisseur of international currency (4)
I believe the answer is:
euro
'international currency' is the definition.
(I've seen this before)
'some connoisseur of' is the wordplay.
'some' indicates a hidden word (some parts of the word are used).
'EURO' is hidden within 'connoisseur of'.
(Other definitions for euro that I've seen before include "European currency" , "wallaroo" , "Foreign currency" , "Basic monetary unit for 19 countries" , "Irish currency" .)