Mac Giolla Deacair
Mac GIOLLA DEACAIR—IV—M'Gilledogher, M'Gilldogher, MacDacker, Harden, Hardy, Harman, Harmon; 'son of Giolla deacair' (hard youth); probably a variant of Mac Dháil-re-dochair, which see. In the 16th century, it was peculiar to Co. Roscommon.
Alphabetical Index to Irish Surnames