stomach upset vs dyspepsia

stomach upset and dyspepsia both are nouns.

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

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

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

Other synonyms of stomach upset include indigestion, upset stomach.

stomach upset (noun)	dyspepsia (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