Expletives are not acceptable behavior on any Stack Exchange site, even on Meta. There are a very small handful of exceptions (such as if you were talking about the word itself on a language site), but in general you should not use expletives anywhere, under any circumstances. If you can't effectively communicate what you need to say without resorting to lowest common denominator cursing, then keep it to yourself.
If you use expletives, you will likely get a warning. Any language that becomes a source of disruption is subject to removal through editing. If you use even what one might consider the mildest of expletives for style and someone removes them, leave them out.
If you continue to use expletives, you will be placed on timed suspension.