good luck vs good fortune

good luck and good fortune both are nouns.

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

As nouns, good luck and good fortune are synonyms defined as:

Other synonyms of good luck include fluke.

As nouns, good luck and good fortune are synonyms defined as:

good luck and good fortune: an auspicious state resulting from favorable outcomes

Other synonyms of good luck include luckiness.

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