Wikipedia:Profanity

Avoid profanity (words or images that could be considered offensive by typical Wikipedia readers), but not at the expense of accuracy. We strive to create a serious encyclopedia with brilliant prose.

Avoid offensive usernames in particular (Wikipedia:No offensive usernames). Most participants feel that tolerating offensive usernames has few if any benefits, but can turn contributors away who see them in the list of recent changes or elsewhere, and this outweighs freedom of expression.

Well written articles should not, on the whole, need to use profanity. However, it may be warranted in some cases: articles specifically about profanity are an example, and when mentioning someone else's use of it, you should go ahead and be accurate.

If you are including some famous person's exact quote, don't censor -- tell us what he actually said, as long as the quote itself is relevant to the article. There's no point in ever turning an instance of "fuck" into "f***" or "the f word"; if you wish to do that you should paraphrase rather than quoting.

Offensive images

this section is tentative

Avoid images that could be considered offensive by typical Wikipedia readers, but again, not at the expense of accuracy. In particular, do not upload any images that could be considered illegal either for you to upload, or for Wikipedia to store, or for Wikipedia readers to download. Note that laws on "obscenity" vary around the world, and Wikipedia should therefore err on the side of safety.

Images, particularly photos, often have a greater impact than words. Therefore, it may be preferable not to embed possibly offensive images in articles, but rather use a [[media:image name]] link with an appropriate warning. On the other hand, if the page title already tells the reader what to expect (e.g. Erotic art in Pompeii), such a warning may be unnecessary.

See also: meta:Should Wikipedia Use Profanity, wikipedia:content disclaimer