rankness vs aroma

rankness and aroma both are nouns.

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

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

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

rankness (noun)	aroma (noun)
the attribute of having a strong offensive smell	any property detected by the olfactory system
the property of producing abundantly and sustaining vigorous and luxuriant growth	a distinctive odor that is pleasant