Polynesian kingdom (5)
I believe the answer is:
tonga
'polynesian kingdom' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for tonga that I've seen before include "Pacific island kingdom" , "Do a bad tango in the Pacific archipelago" , "Polynesian island" , "Relatively small" , "Polynesian monarchy, member of the Commonwealth" .)