altruist vs donor

altruist and donor both are nouns.

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

As nouns, donor is a hypernym of altruist; that is, donor is a word with a broader meaning than altruist:

altruist: someone who makes charitable donations intended to increase human well-being
donor: person who makes a gift of property

Other hypernyms of altruist include bestower, conferrer, giver, presenter.

altruist (noun)	donor (noun)
someone who makes charitable donations intended to increase human well-being	person who makes a gift of property
	(medicine) someone who gives blood or tissue or an organ to be used in another person (the host)