margin vs narrowness

margin and narrowness both are nouns.

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

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

Other hyponyms of margin include margin of error, margin of safety, safety margin, narrow margin, slimness.

margin (noun)	narrowness (noun)
an amount beyond the minimum necessary	the property of being narrow; having little width
a permissible difference; allowing some freedom to move within limits	a small margin
the blank space that surrounds the text on a page	an inclination to criticize opposing opinions or shocking behavior
the amount of collateral a customer deposits with a broker when borrowing from the broker to buy securities	a restriction of range or scope
(finance) the net sales minus the cost of goods and services sold
the boundary line or the area immediately inside the boundary