Largest of the Ryukyu Islands (7)
I believe the answer is:
'largest of the ryukyu islands' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for okinawa that I've seen before include "Japanese location" , "American victory, June 1945" , "Region of southern Japan, scene of fierce fighting in 1945" , "battle!" , "Japanese island captured by US in June nineteen forty five" .)