You can add banned (words considered obscene or forbidden) to the custom dictionaries. Such words will always be considered as misspelled, even if they exist in the main dictionary.

Then, using the spell-check commands, such as Page.PageSpellCheck(<language>,<bSource>) and Ted.GetActiveArticle.SpellCheck (<language>) you perform the spelling check on entire page - and the obscene words will pop-up, even if the rest of the text content is well spelled.

See Adding banned words.