noun
champion; winner; victor; titleholder
Refers to the person who wins a competition, tournament, or contest. Often used in sports, games, and formal contests.
彼は今年のテニス大会の優勝者だ。
He is the champion of this year's tennis tournament.
優勝者にはトロフィーが贈られた。
A trophy was awarded to the winner.
勝者 is a more general term for 'winner' or 'victor' in any contest, whereas 優勝者 implies winning a championship or top prize.
Compound of 優勝 (championship, victory) and 者 (person). The exact historical derivation is straightforward; the word follows a common pattern for forming agent nouns.