golfer vs medal winner

golfer and medal winner both are nouns.

Word	Noun	Adjective	Verb	Adverb
golfer	Yes	No	No	No
medal winner	Yes	No	No	No

As nouns, medal winner is a hyponym of golfer; that is, medal winner is a word with a more specific, narrower meaning than golfer:

Other hyponyms of golfer include driver, golf pro, professional golfer, hacker, hooker, medalist, medallist, putter, slicer.

golfer (noun)	medal winner (noun)
someone who plays the game of golf	(golf) the winner at medal play of a tournament