An Etymological Dictionary of the German Language/verwittern

by Friedrich Kluge

verwittern, vb., ‘to decompose, decay,’ ModHG. only. Allied to E. ‘to wither,’ from MidE. widren, ‘to wither, vanish’; also primitively to Lith. výstu (výsti), ‘to wither,’ pavaitínti, ‘to cause to wither.’