Definition of "verboten"

I read on a notice that one was forbidden to smoke, so to show my ignorance of German I pulled out my pipe. Stumm raised his head, saw what I was doing, and gruffly bade me put it away, as if he were an old lady that disliked the smell of tobacco. In half an hour I got very bored, for I had nothing to read and my pipe was verboten.

1916, John Buchan, “Further Adventures of the Same”, in Greenmantle, London; New York, N.Y.: Hodder and Stoughton, page 63

Before that, students and professors could date whomever we wanted; the next day we were off-limits to one another—verboten, traife, dangerous (and perhaps, therefore, all the more alluring).

2015 February 27, Laura Kipnis, “Sexual paranoia strikes academe”, in The Chronicle of Higher Education‎, Washington, D.C.: Chronicle of Higher Education Inc., archived from the original on 2020-07-22

Or was it because he [Mark Zuckerberg] has since been steeped in the relentless positivity of Silicon Valley, where it is verboten to imagine a bad outcome?

2018 August 2, Kara Swisher, “The expensive education of Mark Zuckerberg and Silicon Valley”, in The New York Times‎, New York, N.Y.: The New York Times Company, archived from the original on 2024-02-17