One of these tripped me up, the "Disallowed Names" section has a bunch of not-too-wordlike names, except one.

When I made carefulwords.com, which I made because I wanted a thesaurus where you could just write eg https://carefulwords.com/book for "book" and get the results, I found out the hard way that you cannot make a file named "con" on Windows. Or "con.html", or any file extension. You can try to force this, make it via a script, but then programs like Git will hang when they come across it. So in my thesaurus the actual page is /con-word.html and I just have it rewrite to /con