Corinthian spirit

noun2

1. •
   An especially high standard of sportsmanship.

   • Another thing the Association fostered, he thought, was the Old Boy spirit -- the Corinthian spirit -- and one way in which that was done was through sport. — 1924
2. •
   (old-fashioned) Amateurism, originally in yachting.

   • An enthusiastic yachtsman, he, in true Corinthian spirit, worked his little craft himself ... — 1886