Religious disaffiliation means that someone who used to believe in a religion or belong to a religious community no longer does. It's like if you used to really love playing with a toy, but now you're not interested in it anymore. Some people might stop believing in a religion because they learn new things that challenge their beliefs, or because they have bad experiences with the people in the religion. Other people might just feel like they don't need a religion to feel happy and fulfilled in their life. Whatever the reason, it's okay to change your mind and beliefs as you grow up and learn more about the world.