An Etymological Dictionary of the German Language/Annotated/verwesen
verwesen, verb, ‘to decay, rot,’ from Middle High German verwësen (Old High German *firwësan), strong verb, ‘to come to nothing, pass away, destroy.’ Compare Gothic frawisan, ‘to consume, waste, squander’ (note frawaírþan, ‘to be destroyed’). However clearly these seem to point to a connection with Wesen (root wës, ‘to be’), yet Old High German wësanên, ‘to get dry, rotten,’ Old Icelandic visenn, ‘faded, decayed,’ and Anglo-Saxon weornían, ‘to destroy,’ suggest a Teutonic and Aryan root wī̆s, ‘to decay,’ from which Greek ἰός, Latin virus (for *visus), Sanscrit viša, ‘poison,’ are derived. —