sweetness vs odour

sweetness and odour both are nouns.

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

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

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

sweetness (noun)	odour (noun)
the property of tasting as if it contains sugar	any property detected by the olfactory system
a pleasingly sweet olfactory property	the sensation that results when olfactory receptors in the nose are stimulated by particular chemicals in gaseous form
the quality of giving pleasure
the taste experience when sugar dissolves in the mouth