An Etymological Dictionary of the German Language/nagen

by Friedrich Kluge

nagen, vb., ‘to gnaw, nibble,’ from the equiv. MidHG. nagen, OHG. nagan, with the earlier variant gnagan; comp. OSax. and AS. gnagan, E. to gnaw, OIc. gnaga, ‘to gnaw.’ There are also forms with initial k instead of g, Du. knagen, OLG. cnagan, likewise HG. chnagan, ‘to gnaw’; the form nagen originated in gnagen. To the Teut. root gnag, knag, no correspondences have been found as yet in the non-Teut. languages.