The Adûnaic name of the river S. Gwathló “Greyflood” (UT/263), also glossed “flood under shadow” (VT42/9). This later name does not fit the Adûnaic phonetic rules described by Tolkien in Lowdham’s Report, since “sh” [ʃ] is not a phoneme used in Adûnaic (SD/418). It may be that Tolkien changed his mind about the phonemes of Adûnaic, or it may be that Agathurush had already undergone some of the phonetic changes leading to the Westron language, which had this sound (LotR/1120). It isn’t clear how this name could be decomposed into its elements.