General terms:
* Hermit: This is the most common term, referring to someone who lives in solitude, often for religious reasons.
* Recluse: A person who lives in seclusion and avoids contact with others.
* Solitarian: Someone who enjoys being alone and prefers to live in solitude.
* Anchorite: Similar to a hermit, but often emphasizes a spiritual or religious motivation.
* Ascetic: A person who practices severe self-discipline and abstains from all forms of indulgence, often for religious reasons.
More specific terms:
* Eremite: A type of hermit who lives in a remote wilderness area.
* Cenobite: A member of a religious community that lives in seclusion, often with a shared rule of life.
* Misanthrope: Someone who dislikes or distrusts humanity. This term can be used to describe someone who withdraws from the world due to their negative view of people.
The specific word you choose depends on the nuances of the situation and the motivations of the person. For example, a person who withdraws from the world due to grief might be called a recluse, while a person who withdraws to focus on their spiritual practice might be called a hermit or an anchorite.