(male) Probably the most successful of all the Old French names of Germanic origin that were introduced to England by the Normans. It is derived from Germanic wil ‘will, desire’ + helm ‘helmet, protection’. The fact that it was borne by the Conqueror himself does not seem to have inhibited its favour with the ‘conquered’ population: in the first century after the Conquest it was the commonest male name of all, and not only among the Normans. In the later Middle Ages it was overtaken by John, but continued to run second to that name until the 20th century, when the picture became more fragmented.
Short forms: Will, Bill.
Pet forms: Willy, Willie, Billy.
Cognates: Irish: Uilliam. Scottish Gaelic: Uilleam. Welsh: Gwilym. German: Wilhelm. Dutch: Willem. Scandinavian: Vilhelm. French: Guillaume. Spanish: Guilermo. Catalan: Guillem. Portuguese: Guilherme. Italian: Guglielmo. Czech: Vilém. Slovenian: Viljem. Hungarian: Vilmos. Lithuanian: Vilhelmas. Latvian: Vilhelms.
Irish (Limerick): Anglicized form of Gaelic Mac Aodha ‘son of Aodh’, an ancient personal name meaning ‘fire’, originally the name of a pagan god. Thus it has the same origin as McGee, McKay and McKee.
FOREBEARS The McCoy clan of KY, led by Randolph McCoy, was involved in one of the bitterest mountain feuds, with the Hatfield clan of WV, from the Civil War to the end of the 19th century. The expression ‘the real McCoy’ probably originated with an American boxer, Norman Selby (1873–1940), who adopted the name “Kid McCoy” distinguish himself from another fighter of the same name.