Recorded as McNiff, MacNuff, McConniff, McCuniff, Mackniffe, Canniffe, Coneffe, Cunniff, Kinniff, and scarcely recognizeable variants such as Caddo, MacAdoo, MacEndoo and others, this is an Irish medieval surname. Also recorded in Scotland for many generations, but in Ireland originally specific to County Leitrim and parts of Ulster, over the centuries it has been recorded in its varied forms throughout Ireland, although it is doubtfull as to the actual relationship between nameholders. However what does seem to be generally agreed is that however the surname is spelt in the 21st century, it derives from the ancient Gaelic word "con" meaning a hound, and "dubh" - black, to give a translation of the Black Hoiund. Most Gaelic surnames are taken from the name of the first chief of the clan or sept, the hound being a popular symbol in heraldry, was also a popular early personal name. It is unclear when the surname was first recorded as many early records were destroyed when the IRA destroyed the Public Records Office in Dublin in 1922, but as MacEniffe and MacNuff it is recorded in County Mayo in 1636, as a Jacobite name in County Monaghan in 1659, whilst in Scotland one John Mackniff is recorded in Lochones in 1674.