If you're looking to ban certain words, phrases or other kind of content, you can always use a bot. Several can be found around the web. These are usually very easy to set up and are pretty accurate. The in-built filter might do the trick as well if you're looking to ban very used indecent phrases or disturbing images. You can find it if you follow this guide: ->Server Settings ->Moderation ->Check "Scan media content from all members."