An Etymological Dictionary of the German Language/rappeln

by Friedrich Kluge

rappeln, vb., ‘to rattle,’ ModHG. only, from LG.; the correct MidHG. form is raffeln, ‘to bluster, clatter’; allied to E. to rap, MidE. rappien. — In the sense of ‘to be crack-brained, rave,’ rappeln may be derived from the meaning ‘to bustle’; it is usually connected, however, with MidHG. (MidG.) rëben, ‘to dream, be confused,’ which is derived from Fr. rêver, whence also E. to rave.