An Etymological Dictionary of the German Language/gaffen
gaffen, vb., ‘to gape at,’ from the equiv. MidHG. (MidG.) gaffen, OHG. *gaffên (deduced from OHG. geffida, f., ‘contemplation’); Goth. *gapan is wanting. The ordinary MidHG. and OHG. words for the modern gaffen are kapfen and chapfên (Goth. *kappan, vb., is wanting). Hence, according to the sounds, the two words are radically different; in the ModHG. period, MidHG. kapfen has given way to gaffen. The latter signifies lit. ‘to look on with open mouth;’ comp. Du. gapen and the equiv. E. to gape, OIc. gapa, ‘to open the mouth wide,’ gap, ‘chaos.’ The Teut. root gap, ‘to gape,’ is allied to Sans. root jabh, ‘to snap’?.