If you harass another player or use hate speech or insults, the moderators (if they catch you) can give a demerit/black spot. This will prevent the player from any chat for a designated time. They may also lose dice spots, tho' I am not sure what significance that has to anything. Demerits are given for unsportsmanlike and bad behavior, which you can report as abuse using the 3 dots at the top of the offending player's profile. If enough demerits are given to a player, they can sometimes be banned.