The Irish for "great-grandfather" is "sinseanathair"; I've never heard a nickname for it, although a nickname for "grandfather" is "daideo". In Irish it's "gar athair"
If your great great great great great grandfather was from Ireland and none of your ancestors in other lines were Irish, then you would be said to be 1/128th Irish. But no one bothers with such small...
Maybe they're all ashamed of being an American and a Citizen of a country who have started and lost more wars than any country, dropped 2 nukes on Japanese Citizens and the cause of the problems in...