The "Real McCoy" 

During the prohibition era, many people became ill or even were killed due to poisonous home-made alcoholic mixtures known as "hooch" or "shine" (short for moonshine). A rumrunner/bootlegger named McCoy had a good three year run using a ship to import genuine alcohol to the united states, and became famous for carrying only the highest quality liquors. His cargo became referred to as the "Real McCoy", and the term became a common way of inquireing as to the authenticity of liquor products, and is commonly used today to inquire as to the authenticity of just about anything. McCoy was intercepted and arrested by the U.S. Coast Guard in 1923.

Is that the "real McCoy"?

The "Real McCoy" by HeliAV8R January 11, 2011

the real mccoy

the genuine article
a true original

the real mccoy by wooster saws September 29, 2003

The real macoy 

term used in the 1920's during prohibition to assure that the liquor you were purchasing on the black market was real; Making sure something is original, real, or authentic.

Are those cigars the real macoy?

Are those breast the real macoy?

Here man its the real macoy.

The real macoy by Carlos R. Gomez V. June 2, 2004