destiny vs good luck

destiny and good luck both are nouns.

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

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

destiny: your overall circumstances or condition in life (including everything that happens to you)
good luck: an auspicious state resulting from favorable outcomes

Other hyponyms of destiny include good fortune, luckiness, providence, bad luck, ill luck, misfortune, tough luck, failure.

destiny (noun)	good luck (noun)
an event (or a course of events) that will inevitably happen in the future	an unexpected piece of good luck
the ultimate agency regarded as predetermining the course of events	a stroke of luck
your overall circumstances or condition in life (including everything that happens to you)	an auspicious state resulting from favorable outcomes