" nonbeliever "

1: a person who does not believe in something (such as a religious belief);

  * e.g., " ... a memorial service that is suitable for both believers and nonbelievers "

•  Synonyms : 

•  atheist,

•  disbeliever,

•  giaour,

•  infidel,

•  misbeliever,

•  miscreant,

•  unbeliever,

•  gentile,

•  heathen,

•  idolater,

•  pagan,

•  doubter,

•  skeptic,

•  agnostic,

•  neo-pagan,

•  polytheist

•  Antonyms : 

•  believer