Dear Quizmaster, ordinarily I don't mind when one of my comments goes unanswered but this one time I am so sure that my opinion is valid and should be addressed that I just can't let it go. The definition of prognosticator is "someone who makes predictions of the future" (https://www.vocabulary.com/dictionary/prognosticator) and is at least as good an answer, if not better, than prophet. If I am in error, please explain! Thank you very much.
Sorry. Most of the "suggestions" that people leave on the vocabulary quizzes are pretty bad so I tend to ignore them. You're right that prognosticator is a good answer, and it will be accepted now.
Most of these work by just putting the part after pro- except for "fane" for profane (but "fanity" works). I know it's my mistake that I shouldn't be lazy but still... I also tried "prostitution" for "promiscuous" but I understand why that one isn't accepted :D