Sultanate hidden in Burnie (6)
I believe the answer is:
brunei
'sultanate' is the definition.
(Brunei is an example)
'hidden in burnie' is the wordplay.
'hidden in' indicates an anagram.
'burnie' is an anagram of 'BRUNEI'.
(Other definitions for brunei that I've seen before include "Sultanate of southeast Asia" , "Muslim state" , "Sultanate on the island of Borneo" , "Rue bin in the sultanate" , "Far Eastern sultanate" .)