the.com/fair play

means Conduct in games, contests, or dealings that follows agreed rules and treats everyone with equal, impartial honesty.

from A straightforward English compound — 'fair' (from Old English fæger, meaning beautiful or pleasing, which drifted toward 'just, even-handed') joined with 'play' in its sense of a game or contest conducted by the rules. The phrase surfaces in English by the 1500s, including in Shakespeare, originally tied to sport and games before spreading to cover any honest, even-handed dealing in business, politics, or life generally.