atheist
The Spanish word 'Ateo' translates to 'Atheist' in English. This term refers to a person who does not believe in the existence of God or gods. An atheist might also reject the belief in any form of spiritual or supernatural realm. In other words, an atheist is someone who lives without any religious beliefs or practices. The term 'Ateo' therefore, is used to describe a person who holds such beliefs in the Spanish-speaking world.
My friend is atheist.
This sentence plainly states that the speaker's friend does not believe in God.
Being atheist, he doesn't go to church.
This sentence explains one of the implications of being an atheist, i.e., not attending church services.
The book was written by an atheist.
This sentence tells us that the person who wrote the book does not believe in any gods.