sweetness vs aroma

sweetness and aroma both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweetness	Yes	No	No	No
aroma	Yes	No	No	No

As nouns, aroma is a hypernym of sweetness; that is, aroma is a word with a broader meaning than sweetness:

Other hypernyms of sweetness include odor, odour, olfactory property, scent, smell.

sweetness (noun)	aroma (noun)
the property of tasting as if it contains sugar	any property detected by the olfactory system
a pleasingly sweet olfactory property	a distinctive odor that is pleasant
the quality of giving pleasure
the taste experience when sugar dissolves in the mouth