medalist vs medal winner

medalist and medal winner both are nouns.

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

As nouns, medalist and medal winner are synonyms defined as:

medalist and medal winner: (golf) the winner at medal play of a tournament

Other synonyms of medalist include medallist.

medalist (noun)	medal winner (noun)
(golf) the winner at medal play of a tournament	(golf) the winner at medal play of a tournament
someone who has won a medal