Nipponese vs Japanese

Nipponese and Japanese both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nipponese	Yes	Yes	No	No
Japanese	Yes	Yes	No	No

As adjectives, Nipponese and Japanese are synonyms defined as:

Nipponese and Japanese: of or relating to or characteristic of Japan or its people or their culture or language

As nouns, Nipponese and Japanese are synonyms defined as:

Nipponese (noun)	Japanese (noun)
a native or inhabitant of Japan	the language (usually considered to be Altaic) spoken by the Japanese
	a native or inhabitant of Japan

Nipponese (adjective)	Japanese (adjective)
of or relating to or characteristic of Japan or its people or their culture or language	of or relating to or characteristic of Japan or its people or their culture or language