donor vs organ donor

donor and organ donor both are nouns.

Word	Noun	Adjective	Verb	Adverb
donor	Yes	No	No	No
organ donor	Yes	No	No	No

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

donor: (medicine) someone who gives blood or tissue or an organ to be used in another person (the host)
organ donor: someone from whom an organ is taken for transplantation

Other hyponyms of donor include blood donor.

donor (noun)	organ donor (noun)
person who makes a gift of property	someone from whom an organ is taken for transplantation
(medicine) someone who gives blood or tissue or an organ to be used in another person (the host)