The denial of death is when people try to ignore or forget that death exists or will happen to them someday. It's like when you cover your eyes during a scary movie, and pretend the scary parts aren't happening. People do this because they are afraid of what will happen after they die, or they don't want to accept that they won't be around forever.
Some people might try to avoid thinking about death altogether, or they might believe in things like heaven or reincarnation to make them feel like death isn't so scary. Others might focus on living a fulfilling life so that they don't have time to think about death.
But even though denying or ignoring death might make someone feel better in the short term, it's important to face the reality of death and plan for it appropriately. This includes making sure your loved ones are taken care of after you're gone, and making the most of the time you have while you're alive.