köken: From Middle High German *īver (“jealousy”). The simplex is first attested in 1494 as yfer, but in 1349 the derivative eifrær (in a southern text that already reflects diphthongisation, thus equivalent to a classical *īverære). An Upper German dialect word, which was chosen by Luther to express the idea of Ancient Greek ζῆλος (zêlos). From the German then Dutch ijver, Middle Low German īver, and…
aile: im Eifer des Gefechts, Glaubenseifer, Übereifer, Wetteifer
köken: From Middle Irish mital, mitall (“metal”), borrowed from Old French metal, from Latin metallum (“metal, mine, quarry, mineral”), from Ancient Greek μέταλλον (métallon, “mine, quarry, metal”).