good luck vs boon

good luck and boon both are nouns.

Word	Noun	Adjective	Verb	Adverb
good luck	Yes	No	No	No
boon	Yes	Yes	No	No

As nouns, boon is a hyponym of good luck; that is, boon is a word with a more specific, narrower meaning than good luck:

Other hyponyms of good luck include prosperity, successfulness, blessing.

good luck (noun)	boon (noun)
an unexpected piece of good luck	a desirable state
a stroke of luck
an auspicious state resulting from favorable outcomes

good luck (adjective)	boon (adjective)
	very close and convivial