Gaelic surnames derived from nicknames include Ó Dubhda (from Aedh ua Dubhda—Aedh, "the dark one"), O'Doherty (from Ó Dochartaigh, "destroyer" or "obtrusive"), Garvery (garbh, "rough" or "nasty"), Manton (mantach, "toothless"), Bane (bán, "white", as in "white hair"), Finn (fionn, "fair", as in "fair hair") and Kennedy (ceann éidigh, "ugly head") Very few Gaelic surnames are derived from placenames or from venerated people or objects.
Among those that are included in this small group, several can be shown to be derivations of Gaelic personal names or surnames.
For much the same reason, nicknames (e.g. "the Fada Burkes", "the long/tall Burkes"), father's names (e.g. "John Morrissey Ned") or mother's maiden name ("Kennedy" becoming "Kennedy-Lydon") can become colloquial or legal surnames.
The Irish family of de Courcy descends from Anglo-Normans who came to Ireland following the Norman Conquest; the name is of French derivation, and indicates that the family once held a manor of that name in Normandy.
[1] In addition to all this, Irish-speaking areas still follow the old tradition of naming themselves after their father, grandfather, great-grandfather and so on.