Religionless is a word used to describe someone who does not adhere to any religious beliefs or practices. Some synonyms for religionless include secular, agnostic, atheistic, non-believing, and non-theistic. Secular refers to a person who is not concerned with religion or religious affairs. An agnostic is someone who believes that it is impossible to determine whether or not God exists. On the other hand, an atheist is someone who believes that God does not exist. Non-believing and non-theistic both refer to individuals who do not believe in any deity or religious doctrine. These synonyms can be used interchangeably to discuss someone who lives their life without a religious belief system.