unberufen

From German unberufen (“let it not be called down on me”)

unberufen

1. (dated) Touch wood; knock on wood; an injunction to fate that nothing will go wrong.
   • 1883, Rhoda Broughton, Belinda

     "Unberufen ! " cries Sarah, with a shudder that is not all affectation, " do not mention that accursed name ; I could have sworn that I heard her voice just now !"

   • 1904, Ralph Henry Barbour, Kitty of the roses

     " Unberufen !" he cried. "Unberufen!" she echoed. Then their glances met and they laughed...

   • 1905, Anna Chapin Ray and Hamilton Brock Fuller, On the Firing Line‎, EBook edition, Project Gutenberg, published 2009:

     Bending over, Ethel turned back the cloth and thumped on the under side of the table. / "Unberufen and Absit omen," she said hastily. "Don't tempt Providence too far, Captain Frazer. …"

   • 1920, Percy Lubbock (ed.), The Letters of Henry James

     And I am working so well (unberufen!) with my admirable Secretary; I shouldn't really dare to ask her to join our little caravan...