Jap vs Japanese

Jap and Japanese both are nouns.

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

As nouns, Japanese is a hypernym of Jap; that is, Japanese is a word with a broader meaning than Jap:

Other hypernyms of Jap include Nipponese.

Jap (noun)	Japanese (noun)
(offensive slang) offensive term for a person of Japanese descent	the language (usually considered to be Altaic) spoken by the Japanese
	a native or inhabitant of Japan

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