misadventure vs misfortune

misadventure and misfortune both are nouns.

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

As nouns, misfortune is a hypernym of misadventure; that is, misfortune is a word with a broader meaning than misadventure:

misadventure: an instance of misfortune
misfortune: unnecessary and unforeseen trouble resulting from an unfortunate event

Other hypernyms of misadventure include bad luck.

misadventure (noun)	misfortune (noun)
an instance of misfortune	unnecessary and unforeseen trouble resulting from an unfortunate event
	an unfortunate state resulting from unfavorable outcomes