[(folk etymology) the just, the righteous].
One of six chiefs of the Tuatha Dé Danann who was described as taking mortals to his ‘castle’ at Knockfeerina, also Knockfierna [Ir. Cnoc Fírinne], in south-west Co. Limerick near Ballingarry. Käte Müller-Lisowski argued that this figure is derived from Donn (1), the god of the dead: ‘Donn of Cnoc Fírinne’, Béaloideas, 18 (1948), 142–99.