dyspepsia vs stomach upset

dyspepsia and stomach upset both are nouns.

Word	Noun	Adjective	Verb	Adverb
dyspepsia	Yes	No	No	No
stomach upset	Yes	No	No	No

As nouns, dyspepsia and stomach upset are synonyms defined as:

dyspepsia and stomach upset: a disorder of digestive function characterized by discomfort or heartburn or nausea

Other synonyms of dyspepsia include indigestion, upset stomach.

dyspepsia (noun)	stomach upset (noun)
a disorder of digestive function characterized by discomfort or heartburn or nausea	a disorder of digestive function characterized by discomfort or heartburn or nausea