setback vs occurrence

setback and occurrence both are nouns.

Word	Noun	Adjective	Verb	Adverb
setback	Yes	No	No	No
occurrence	Yes	No	No	No

As nouns, occurrence is a hypernym of setback; that is, occurrence is a word with a broader meaning than setback:

setback: an unfortunate happening that hinders or impedes; something that is thwarting or frustrating
occurrence: an event that happens

Other hypernyms of setback include happening, natural event, occurrent.

setback (noun)	occurrence (noun)
an unfortunate happening that hinders or impedes; something that is thwarting or frustrating	an event that happens
	an instance of something occurring