Having your profanity filter on will mean any swearing or offensive language will be starred out.
Once enabled, the filter works within all of the chat channels: All Chat, Private Chat, Friends Chat, Clan Chat, Guest Clan Chat, Trade and Assistance.
Follow these steps to toggle your profanity filter in either game version.
|1||Head to Private Chat|
|2||Click the cog and turn the profanity filter 'On'|
Old School RuneScape
|1||Click the in game spanner and go to All Settings|
|2||In the Settings menu, type 'Profanity Filter' and uncheck the box to enable the filter|