width vs narrowness

width and narrowness both are nouns.

Word	Noun	Adjective	Verb	Adverb
width	Yes	No	No	No
narrowness	Yes	No	No	No

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

Other hyponyms of width include broadness, wideness, beam.

width (noun)	narrowness (noun)
the extent of something from side to side	the property of being narrow; having little width
	a small margin
	an inclination to criticize opposing opinions or shocking behavior
	a restriction of range or scope