deficiency vs poorness

deficiency and poorness both are nouns.

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

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

deficiency (noun)	poorness (noun)
lack of an adequate quantity or number	the quality of being poorly made or maintained
the state of needing something that is absent or unavailable	less than adequate
	the quality of being meager
	the state of having little or no money and few or no material possessions