For questions about usage of profanities and offensive language.
Profanities are language and words that are offensive, obscene or blasphemous, usually considered unacceptable for respectful and formal discourse.
Wikipedia has a rich page about profanities in Mandarin.
Use this tag [swearing] for questions about offensive language and words. It might be a good idea to add other tags that specify whether you are interested in [mandarin], [cantonese] or some other [topolect].
Note that colloquial and slang words are not necessarily profanities. While slang might be inappropriate in certain social situations, it's not automatically rude or abusive. For such questions, use [colloquialisms] or [slang] instead.