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 of the parts of the word are used).
'EURO' is hidden in the letters of '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" .)