@ProfKinyon - more like "fake, unreliable educated guess".
@johncarlosbaez "Ersatz" certainly has a negative connotation, but I think that if you were to put them all on a scale, it's somewhat more neutral than many of the others in that list.
It's been many years, but I still remember the first time I heard a speaker use "ansatz" during a mathematics talk. I like to use it whenever I can when I teach, since it's such a cool word.
@ProfKinyon @johncarlosbaez what makes you so confident you use the word correctly. I studied in Germany and don't remember ever hearing it used as in "educated guess". I see it more as "predisposition", "approach". Then the dictionary doesn't completely agree https://dict.leo.org/german-english/ansatz
@johncarlosbaez thanks for clarifying. As I've learned my English-language maths terminology in Germany, I had never before come across this explanation, and it has left me wondering on several occasions before. Your reference is much appreciated