Ó Claimhín
Ó CLAIMHÍN, Ó CLAMHÁIN—I—O Clavan, Clavan, Claveen, Clavin, Swords, &c.; 'descendant of Claimhín' or 'Clamhán' (diminutive of clamh, a sick person, a leper); a not uncommon surname in Mayo, but generally anglicised Swords, which is supposed to be a translation. Compare with claidheamh, a sword.
Alphabetical Index to Irish Surnames