Indonesian vs Papuan

Indonesian and Papuan both are nouns.

Word	Noun	Adjective	Verb	Adverb
Indonesian	Yes	Yes	No	No
Papuan	Yes	Yes	No	No

As nouns, Papuan is a hyponym of Indonesian; that is, Papuan is a word with a more specific, narrower meaning than Indonesian:

Other hyponyms of Indonesian include Sumatran, Javan, Javanese.

Indonesian (noun)	Papuan (noun)
the dialect of Malay used as the national language of the Republic of Indonesia or of Malaysia	any of the indigenous languages spoken in Papua New Guinea or New Britain or the Solomon Islands that are not Malayo-Polynesian languages
a native or inhabitant of Indonesia	a native or inhabitant of Papua New Guinea or New Guinea

Indonesian (adjective)	Papuan (adjective)
of or relating to or characteristic of Indonesia or its people or languages	of or relating to Papua or its people or language