An Etymological Dictionary of the German Language/verwesen

by Friedrich Kluge

verwesen, vb., ‘to decay, rot,’ from MidHG. verwësen (OHG. *firwësan), str. vb., ‘to come to nothing, pass away, destroy.’ Comp. Goth. 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 OHG. wësanên, ‘to get dry, rotten,’ OIc. visenn, ‘faded, decayed,’ and AS. weornían, ‘to destroy,’ suggest a Teut. and Aryan root wī̆s, ‘to decay,’ from which Gr. ἰός, Lat. virus (for *visus), Sans. viša, ‘poison,’ are derived. —