mishap vs bad luck

mishap and bad luck both are nouns.

Word	Noun	Adjective	Verb	Adverb
mishap	Yes	No	No	No
bad luck	Yes	No	No	No

As nouns, bad luck is a hypernym of mishap; that is, bad luck is a word with a broader meaning than mishap:

mishap: an instance of misfortune
bad luck: unnecessary and unforeseen trouble resulting from an unfortunate event

Other hypernyms of mishap include misfortune.

As nouns, mishap and bad luck are synonyms defined as:

Other synonyms of mishap include mischance.

mishap (noun)	bad luck (noun)
an instance of misfortune	unnecessary and unforeseen trouble resulting from an unfortunate event
an unpredictable outcome that is unfortunate	an unpredictable outcome that is unfortunate
	an unfortunate state resulting from unfavorable outcomes