From an ancient Gaelic-Irish name. MacGiolla Deacair. Deacair is the Irish word for hard. The early anglicized form of this name was Macgilledogher. Now obsolete and in the absence of a reliable pedigree it is not possible to distinguish between Hardys of English and Hardys of Irish origin. In this regard it is of interest to remember that the sept of Macgilledogher was located in Co. Roscommon.