Ó Muimhnigh
Ó MUIMHNIGH—I—O Moyney, O Moynig, Moyney, Mooney; 'descendant of Muimhneach' (Munsterman); the name of a family of Corca Laoighdhe, in South-West Cork. It is not improbable that it has been changed in most instances to the diminutive Ó Muimhneacháin (which see) now so common in West Cork and Kerry.
Alphabetical Index to Irish Surnames