Capital on the island of Luzon (6)
I believe the answer is:
manila
'capital on the island of luzon' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for manila that I've seen before include "Strong brown paper originally made from hemp" , "Animal or capital in the Phillipines" , "Animal found in Philippines" , "Adulterated, tainted" , "Strong brown paper; cigar, cheroot" .)