{} would be a fairly safe word choice here. Literally, that means "the words forbidden on the air". Though it uses six kanji, it is not a heavy-sounding word at all.
If you used a more "dictionary translation" kind of word such as {} or {}{}, it would be much more uncommon and it would sound much heavier and technical.
{} means a totally different thing. It means "abuse", "slander", etc. It refers to the action and not the words uttered themselves.