An Etymological Dictionary of the German Language/laufen
laufen, vb., ‘to run,’ from the equiv. MidHG. loufen, OHG. louffun, str. vb.; from an earlier hlauffan, equiv. to Goth. hlaupan, ‘to run.’ It corresponds to AS. hleápan, str. vb., ‘to run, leap, dance,’ E. to leap, Du. loopen, OIc. hlaupa; a specifically Teut. word common to all the dialects. For the prim. meaning we have absolutely no clue (Gr. κραιπνός, ‘swift,’ is not allied to Goth. hlaupan, which may be preferably compared with Lith. klupti, ‘to stumble’). The Teut. root hlaup has a collateral form hlŭp, by gradation hlŏp (MidHG. and ModHG. dial. geloffen, partic.), of which a variant hlaubt appears in Swiss lôpen, ‘to run’ (comp. hüpfen, Bav. hoppen). ModHG. Lauft, plur. Läufte, m., from the equiv. MidHG. and OHG. louft, m., ‘course (of time),’ (MidHG. plur. löufte, ‘conjunctures’).