special interest vs NRA

special interest and NRA both are nouns.

Word	Noun	Adjective	Verb	Adverb
special interest	Yes	No	No	No
NRA	Yes	No	No	No

As nouns, NRA is a hyponym of special interest; that is, NRA is a word with a more specific, narrower meaning than special interest:

special interest: an interest group that tries to influence legislators or bureaucrats to act in their favor, typically through lobbying
NRA: a powerful lobby that advocates the right to own and bear arms and rejects any gun regulation by the government

Other hyponyms of special interest include National Rifle Association.

special interest (noun)	NRA (noun)
an interest group that tries to influence legislators or bureaucrats to act in their favor, typically through lobbying	a powerful lobby that advocates the right to own and bear arms and rejects any gun regulation by the government