An Etymological Dictionary of the German Language/läugnen
läugnen, vb., ‘to contradict, deny,’ from the equiv. MidHG. löugenen, lougenen, lougen, OLG. louginen, lougnen, wk. vb.; corresponding to OSax. lôgnian, AS. lêhnan, lŷgnan, Goth. laugnjan, wk. vb., ‘to deny’; OIc. leyna, ‘to conceal’ (Goth. galaugnjan, ‘to be concealed’), with the loss of a g before the n. A common Teut. wk. vb. with the meaning ‘to deny’; it is a derivative of an OHG. noun lougna, f., ‘denial’ (OIc. laun), which is formed by gradation from the stem of lügen (root lug). Comp. lügen.