An Etymological Dictionary of the German Language/Annotated/Schweif
Schweif, masculine, ‘tail, train, suite,’ from Middle High German sweif, masculine, ‘rotation, encircling band, trimming of a garment, tail,’ Old High German sweif, Old Icelandic sveipr, ‘encircling band’; allied to Old High German sweifan, ‘to cause to rotate, turn.’ With the Teutonic root swaip, Greek σόβη, ‘horsetail,’ cannot be connected. See the following word.