You can use the supplemental lexicon for the specific or for all languages also to add banned words.
To add a banned word
1.Locate the supplemental lexicon as explained in Supplemental lexicon for the specific language and Supplemental lexicon for all languages.
2.Open the supplemental lexicon in Notepad or similar.
3.Add one banned word by line, followed by a tab and the e code, e.g.
obscene e
Note
Make sure that you pressed Return on the end of the last line.