An Etymological Dictionary of the German Language/schwindeln

by Friedrich Kluge

schwindeln, vb., ‘to be dizzy or giddy,’ from the equiv. MidHG. swindeln, OHG. swintilôn, allied to MidHG. swindel, ‘giddiness, vertigo,’ equiv. to OHG. swintilôd and swintilunga. Further akin to schwinden, ‘to dwindle away,’ hence MidHG. also ‘to faint, become unconscious.’