New Guinea
geographical name
1
or Papua island of the Malay Archipelago in the western Pacific north of eastern Australia; divided between Indonesia on the west and Papua New Guinea on the east area over 305,000 square miles (789,950 square kilometers)
Note: Exclusive of Australia, New Guinea is the second largest island in the world.
2
the northeastern portion of the island of New Guinea which was formerly a territory and is now part of Papua New Guinea see north-east new guinea
New Guinean
ˈgi-nē-ən 
adjective or noun