Green’s Dictionary of Slang

a one-sided sports contest; a rout; lit. something considered risible.

1976		D. Hall Dock Ellis 75: The last of the three losses in L.A. was a laugher, six to nothing.
1991		J.B. Holway Josh & Satch 79: Every one was a complete game, except for one 15—3 laugher.
1994		M. Ribowsky Don’t Look Back 55: Satch racked up two shutouts against Memphis, a 10-strikeout, 2-0 beauty [...] and a 10-0 laugher.