the real McCoy

1. The best of its kind, the real thing: “That homemade pizza was the real McCoy.” The source of this expression is the story of a famous prizefighter named McCoy. He had so many imitators that no one was sure which was the real one.

Idioms and Phrases

Also, the McCoy. The genuine thing, as in That painting's not a reproduction—it's the real McCoy. This idiom has a disputed origin, but the most likely source is its use to distinguish welterweight champion “Kid McCoy,” the name used by Norman Selby (1873-1940), from other boxers using his name to capitalize on his popularity. [c. 1900]