Recorded in many spelling forms including Mahady, Mahaddie, MacHadie, Mahadie, Mahaddy, Mahedy, Mahody and no doubt others, this is an Irish clan surname. The original territory of the clan lay mainly in County Longford, with some presence in the adjoining Westmeath and Roscommon. Despite the apparent number of spelling forms it is also very rare. It derives from the pre 10th century Old Gaelic surname "O Moithide", with the prefix "O" indicating descendant or possibly grandson of, although the meaning of the personal name "Moithide" remains obscure. Its roots may lie in the word "moite", meaning exception; hence, the descendant of the exceptional one. Another similar etymology is from the word "mothaigh", meaning to sense or perceive, thereby implying "the descendant of the perceptive one". Traditionally, Irish family names are taken from the the nickname for the original head of the clan or tribes or from some equally associated illustrious warrior, and were originally almost always with the prefix of O' or Mac denoting "son of". The first recorded spelling of the family name may be that of John Maddy. He was a christening witness at Derry Cathedral, Templemore, County Derry, on October 20th 1660. Later examples include John Mahady who married Mary Delany at Mallow, County Cork, on October 19th 1810, Thomas Mahedy of Ballycastle, County Mayo, on August 13th 1863, and Patrick Mahaddy of Ruskey, County Roscommon, on September 20th 1865. Group Captain Hamish Mahaddy was a famous RAF pilot in the Second World War (1939 - 1945).