luck vs misfortune

luck and misfortune both are nouns.

Word	Noun	Adjective	Verb	Adverb
luck	Yes	No	No	No
misfortune	Yes	No	No	No

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

luck: your overall circumstances or condition in life (including everything that happens to you)
misfortune: an unfortunate state resulting from unfavorable outcomes

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

luck (noun)	misfortune (noun)
an unknown and unpredictable phenomenon that causes an event to result one way rather than another	unnecessary and unforeseen trouble resulting from an unfortunate event
an unknown and unpredictable phenomenon that leads to a favorable outcome	an unfortunate state resulting from unfavorable outcomes
your overall circumstances or condition in life (including everything that happens to you)