Pacific island, genuine and raw, deposing King in rebellion (3,6)
I believe the answer is:
new guinea
'pacific island' is the definition.
(I've seen this before)
'genuine and raw deposing king in rebellion' is the wordplay.
'and' is a charade indicator (letters next to each other).
'deposing' is a deletion indicator.
'king' becomes 'R' (abbreviation for rex, king in Latin).
'in rebellion' indicates anagramming the letters.
'genuine' put after 'raw' is 'rawgenuine'.
'rawgenuine' with 'r' taken away is 'awgenuine'.
'awgenuine' anagrammed gives 'NEW GUINEA'.
(Other definitions for new guinea that I've seen before include "Island in the Western Pacific" , "Pacific island, the world's second largest" , "divided island" , "Papua - - - -" .)