v1.0
Published 01/10/24
1brat m. [b̥ɾaʰt̪], gen. brata -[ə], also brot, ‘cloak, mantle’ is considered by McDonald (2009, 346) a likely loan from ON brot-, as in brothvítill m. ‘cover, blanket’, after Marstrander (1915a, 38, 64), but who (p. 150) takes ON brot- to be a diminutive prefix in the sense ‘poor or worn out’. SG brat (OG bratt) is no doubt Celtic in origin (e.g. MacBain 1911); indeed, Falk (1919, 205–06) takes ON brot- to be loan from OG bratt or SG brat (brot).
So also de Vries 1962.