non-Christian       
 adjective uk/ˌnɒnˈkrɪs.tʃən/ us/ˌnɑːnˈkrɪs.tʃən/
 非基督徒的
not belonging to the religion based on the teachings of Jesus Christ
  She has many non-Christian friends. 她有很多非基督徒朋友。 
 The Pope met with representatives of several non-Christian faiths.
 - More examples
 - Many non-Christian faiths also stress the importance of family and relationships.
 - Muslims form the largest non-Christian religious group in Great Britain.
 - I do not want to offend people of non-Christian faiths.
 
non-Christian        
noun [ C ] uk/ˌnɒnˈkrɪs.tʃən/ us/ˌnɑːnˈkrɪs.tʃən/
 非基督徒
someone who does not believe in and follow the teachings of Jesus Christ
  We are trying to encourage friendship between Christians and non-Christians.
 Her family disapproved of her marrying a non-Christian. 她的家人不赞成她嫁给一个非基督徒。 
 - More examples
 - Asking a person for their "Christian name" could be offensive to non-Christians.
 - The course is designed to teach non-Christians about the basics of the Christian faith.