Taboo on the dead means that in some cultures it is seen as wrong or bad to talk about or do certain things related to the dead. In some cultures, it might be considered disrespectful to tell stories or jokes about a person that has died. People might also avoid talking about how the person died or visiting the place where the person died, or use the name of the person when talking about them. This can help people feel like they are respecting the dead person and their memory.