A coin's rolling around island capital (7)
I believe the answer is:
nicosia
'capital' is the definition.
(capital of Cyprus)
'a coin's rolling around island' is the wordplay.
'rolling' is an anagram indicator.
'around' is an insertion indicator.
'island' becomes 'i' (geographical abbreviation).
'a'+'coins'='acoins'
'acoins' is an anagram of 'nicosa'.
'nicosa' placed around 'i' is 'NICOSIA'.
(Other definitions for nicosia that I've seen before include "Divided Cypriot capital" , "Largest city on Cyprus" , "European Union's most southerly capital" , "capital city" , "Casino I find in Cyprus - that's capital" .)