margin vs narrow margin

margin and narrow margin both are nouns.

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

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

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

margin (noun)	narrow margin (noun)
an amount beyond the minimum necessary	a small margin
a permissible difference; allowing some freedom to move within limits
the blank space that surrounds the text on a page
the amount of collateral a customer deposits with a broker when borrowing from the broker to buy securities
(finance) the net sales minus the cost of goods and services sold
the boundary line or the area immediately inside the boundary