rot vs rottenness

rot and rottenness both are nouns.

Word	Noun	Adjective	Verb	Adverb
rot	Yes	No	Yes	No
rottenness	Yes	No	No	No

As nouns, rottenness is a hyponym of rot; that is, rottenness is a word with a more specific, narrower meaning than rot:

Other hyponyms of rot include corruption, putrescence, putridness.

rot (noun)	rottenness (noun)
unacceptable behavior (especially ludicrously false statements)	the quality of rotting and becoming putrid
(biology) the process of decay caused by bacterial or fungal action	in a state of progressive putrefaction
a state of decay usually accompanied by an offensive odor

rot (verb)	rottenness (verb)
become physically weaker
break down