Is it permissible to act out or imagine death with all its details, and is that considered lying, and what is the definition of prohibited lying?

Lying is intentionally informing about something contrary to its reality, and it is a major sin that leads to Hellfire. However, feigning death or imagining it is not considered a lie because it is not an act of informing. This imagination might be praiseworthy if its intention is to preach, instill fear of Allah, and encourage good deeds. As for doing it frivolously, it is not appropriate due to the waste of time involved. A wise person should utilize their time in what benefits them in this world and the Hereafter.