'prohibited topics' is correct and usable in written English.
It is used to refer to topics which are not to be discussed or are considered off-limits. For example, "Our company policy states that we are not to discuss politics or religion—these topics are considered prohibited topics."
The state's prohibited "red line" topics include the covert wars in Darfur, and Blue Nile and South Kordofan states.
China's control of news, messages and information is vast and ranges from instructions to news media about what to report, to pressure on academic journals and book publishers about what to print, to surveillance of social media for posts that might touch third-rail topics prohibited by the party, such as the 1989 Tiananmen Square massacre.
The lack of well-conducted studies or randomised trials on the topic prohibited us from conducting a meta-analysis and quantifying dental erosion.
One executive, whose firm prohibited discussing the topic with the news media, said the bump in base salaries had confused people, even though their overall compensation was the same.
Even 4chan's /v/ board initially prohibited threads on the topic.
They founded Al-Jazeera as a broadcasting network that enjoys much more freedom to report and engage in political and religious topics that are prohibited in Saudi Arabia reporting that has irritated the Al-Sauds to no end.
That doesn't mean that writing about commercial topics is completely prohibited, however.
Advocates of intelligent design's constitutionality often argue that public school teachers have a First Amendment academic freedom right to teach intelligent design even if the school or school board has prohibited teachers from discussing the topic.
The filmmakers have managed to raise the money to rate the film, but were slapped with an R rating when the film should clearly be a PG-13, especially since the demographics that would most benefit seeing a documentary of this topic are religiously prohibited from seeing an R rated film.
The law actually does its best to discourage scientific data on this topic, prohibiting Department of Education surveys from asking students, even anonymously, about their sex behavior or attitudes.
Wh-extraction and topic extraction is not prohibited in ki' LA constructions.
