An Etymological Dictionary of the German Language/Annotated/Reue
Reue, feminine, ‘repentance, from Middle High German riuwe, feminine, ‘sadness, pain, mourning, repentance,’ Old High German riuwa, earlier hriuwa, feminine; corresponding to Dutch rout, Anglo-Saxon hreów, ‘grief, mourning, repentance.’ Allied to an obsolete Old High German verb hriuwan, Middle High German riuwen, ‘to feel pain, be sorry’; corresponding to Anglo-Saxon hreówan, ‘to vex, grieve,’ English to rue, to which ruth is akin; Old Icelandic hryggva, ‘to sadden.’ Gothic *hriggwan wanting. The Teutonic hrū̆, ‘to be sad, sadden,’ has no correspondences in the other Aryan languages.