Dan

Clifford was christened Eamonn (Irish form of Edward). Born in Cork (c. 1915), he spent his childhood in Kerry before moving to Dublin, where he worked as a civil servant. He was also a poet, playwright and composer of ballads. He used "Sigerson Clifford" as a pen-name. Sigerson was his mother's maiden name! He died around 1985.

Of course - that doesn't really answer your question! McLysaght's book "Surnames of Ireland" lists the name and says roughly: "..of Norse origin, this name has been in Ireland since at least the 16th C. Now largely confined to Kerry."

Mind you - the Norse/Danes were ejected from Ireland in the 11th century, so there's still a gap to be explained!

Regards