1680s, "one skilled in medals," from medal (n.) + -ist. Meaning "medal-maker" is from 1756; that of "recipient of a medal" is from 1797.

the player in a stroke play, or medal play, competition with the fewest strokes/lowest score; the winner Example: The medalist received the maximum award allowable by the rules of golf for an amateur.

the player in a stroke play, or medal play, competition with the fewest strokes/lowest score, the winner

The winner of a stroke play is designated as medalist. This term has its origin on the one hand side in there, that he earns a medal, on the other hand side another name for stroke play is medal play, hence in both variations the winner is the medalist. Sometimes there are match play tournaments, which begin with one or two rounds of stroke play. T [..]

To put it in least complex words, it means the winner of a medal play or stroke play in any golf tournament.

refers to the lowest qualifying score of a tournament player.

The player with the lowest qualifying score in a tournament.

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