Ó Fuathmharáin
Ó FUATHMHARÁIN—I—O Whoheran, (?) Forhan; 'descendant of Fuathmharán' (diminutive of fuathmhar, hateful); also written Ó hUathmharáin; the name of a family of the Ui Fiachrach who were anciently seated in the parish of Ballintobber, Co. Mayo. In the 16th century, it was found in Westmeath, but was very rare, and is probably now obsolete.
Alphabetical Index to Irish Surnames