Deism is the belief in a God who created the world but hasn’t gotten involved with people since then — as opposed to theism, whose God still takes an active role in the world.
According to deism, the creator has a hands-off approach and lets people fend for themselves. Originally the word was used to mean a belief in a deity (as theism is used now), in contrast to atheism, which lacks a God at all. Deism as it is used now is associated with the Enlightenment movement of the 17th and 18th century. A person who believes in deism is a deist.