the genuine thing or person as promised, stated, or implied (usually preceded by the or the real ): Those other paintings are copies, but this one is the McCoy.
Origin: 1880–85; also Mackay, McKie, the clear McCoy (of liquor); of uncertain origin; hypothesized identifications with Mackay, a Scottish clan, and Kid McCoy, nickname of U.S. boxer Norman Selby (1873–1940), are unsubstantiated
slang the genuine person or thing (esp in the phrase the real McCoy)
[C20: perhaps after Kid McCoy, professional name of Norman Selby (1873--1940), American boxer, who was called ``the real McCoy'' to distinguish him from another boxer of that name]
as in the real McCoy, 1922, from Scot. the real Mackay (1883), of uncertain origin, though there are many candidates, including whiskey distilled by A. and M. Mackay of Glasgow (the phrase the real McCoy became popular during Prohibition to describe liquor); Charles S. "Kid" McCoy (1872-1940), former
welterweight boxing champ; and a claimant for chief of the northern branch of the clan Mackay.
n. something authentic. : This is the real McCoy. Nothing else like it.
n. pure drugs or alcohol. : If it's not the real McCoy, I don't want it.
Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition. Copyright 2007. Published by McGraw Hill.
Cite This Source