An Etymological Dictionary of the German Language/Tausch
Tausch, m., ‘exchange, barter’; ModHG. only; in late MidHG. (15th cent.) we meet for the first time with rostiuchœre, ‘horse-dealer’ (comp. Du. paardentuischer), and verûschen, ‘to exchange.’ The word is properly LG.; comp. Du. tuischen, ‘to barter.’ How täuschen, ‘to deceive,’ from late MidHG. tiuschen (tûschen), ‘to deceive, make game of some one’ (late MidHG. tûsch, ‘mockery, joke, deception’), is connected with this word is not clear.