Where does “irskhed” come from?

irskhed (Danish) comes from Danish irsk, from Old Norse írskr, from Old Norse Írar, from Old Irish Ériu, from Primitive Irish *Īweriū, from Proto-Celtic Φīweryū, from Proto-Indo-European piHweryon-, from Proto-Indo-European peyH- — fat, milk.

irskhed (Danish): Irishness