acidity vs sour

acidity and sour both are nouns.

Word	Noun	Adjective	Verb	Adverb
acidity	Yes	No	No	No
sour	Yes	Yes	Yes	No

As nouns, acidity and sour are synonyms defined as:

Other synonyms of acidity include sourness.

As nouns, sour is a hypernym of acidity; that is, sour is a word with a broader meaning than acidity:

acidity: the taste experience when something acidic is taken into the mouth
sour: the taste experience when vinegar or lemon juice is taken into the mouth

Other hypernyms of acidity include sourness, tartness.

acidity (noun)	sour (noun)
pH values below 7	the property of being acidic
the property of being acidic	the taste experience when vinegar or lemon juice is taken into the mouth
the taste experience when something acidic is taken into the mouth	a cocktail made of a liquor (especially whiskey or gin) mixed with lemon or lime juice and sugar

acidity (adjective)	sour (adjective)
	having a sharp biting taste
	showing a brooding ill humor
	inaccurate in pitch
	smelling of fermentation or staleness
	in an unpalatable state
	one of the four basic taste sensations; like the taste of vinegar or lemons

acidity (verb)	sour (verb)
	go sour or spoil
	make sour or more sour