Usage examples for racehorse:

• He talked like a racehorse approaching the winning- post. "Collections and Recollections" – George William Erskine Russell

• On hearing the report, it turned round and set off, running with the speed of a racehorse across the country, while we stood gazing after it, and, as Paddy observed, looking very foolish. "Twice Lost" – W.H.G. Kingston

• Big Bill, acting foreman now, took upon himself the unremitting work of making the racehorse fit. "The Short Cut" – Jackson Gregory