Hardiman, Harmon
Hardiman, Harmon—These two names are the anglicised forms of O'h-Argadáin; the first in the districts surrounding Galway City, and the second, Harmon, in that county and those adjoining.
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees