Ó Flaithimh
Ó FLAITHIMH—I—O Flahiff, O Flahie, Flahive, Flahy; 'descendant of Flaitheamh' (lord, ruler); a scattered surname. In the 16th century, it was found in Galway, Clare, Tipperary, Kilkenny and Wexford. It is now often changed, by the aspiration of the initial f, to Ó Laithimh, which see. Also Ó Flathaigh, which see.
Alphabetical Index to Irish Surnames