inadequacy vs poorness

inadequacy and poorness both are nouns.

Word	Noun	Adjective	Verb	Adverb
inadequacy	Yes	No	No	No
poorness	Yes	No	No	No

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

inadequacy (noun)	poorness (noun)
unsatisfactoriness by virtue of being inadequate	the quality of being poorly made or maintained
lack of an adequate quantity or number	less than adequate
a lack of competence	the quality of being meager
	the state of having little or no money and few or no material possessions