feast vs luau

feast and luau both are nouns.

Word	Noun	Adjective	Verb	Adverb
feast	Yes	No	Yes	No
luau	Yes	No	No	No

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

feast: an elaborate party (often outdoors)
luau: an elaborate Hawaiian feast or party (especially one accompanied by traditional foods and entertainment)

Other hyponyms of feast include potlatch.

feast (noun)	luau (noun)
something experienced with great delight	an elaborate Hawaiian feast or party (especially one accompanied by traditional foods and entertainment)
an elaborate party (often outdoors)
a meal that is well prepared and greatly enjoyed
a ceremonial dinner party for many people

feast (verb)	luau (verb)
partake in a feast or banquet
provide a feast or banquet for
gratify