chalk eater

plural chalk eaters

1. slangOne who bets on racehorses that are favourites to win.

   At six major race tracks across the nation, chalk-eaters (form players) were choking last weekend over a straight flush of longshots.

   1949, Time, volume 54, page 36

   1 more example

   Of horse players and the ragged army of grifters, touts and downright swindlers who attach themselves to the noble sport of kings there is no end of stories. Get a few of the chalk eaters and long shot hounds together during a lull in the day's occupation—picking the next day's card of winners—and the tales begin to come, thick and fast.

   1953, Mac Davis, Say it Ain't So!, page 149

   Synonyms: chalk player