Infidel

Christians have historically referred to people outside their religious group as infidels, somebody who has actively rejected the Christian religion. It only became a well established notion in English sometime in the early sixteenth century, when Jews or "Mohammedans", were described as active opponents to Christianity, and as such infidel was seen as term of contempt. In Catholic doctrine, an infidel is one who does not believe in the doctrine at all and is thus distinct from a heretic, who is one seen as having fallen astray from true doctrine, i.e. by denying the divinity of Jesus. Similarly, the ecclesiastical term was also used by the Methodist Church,[11][12] in reference to those "without faith".[13]

Today, the usage of the term infidel has declined;[14] the current preference is for the terms non-Christians and non-believers (persons without religious affiliations or beliefs), reflecting the commitment of mainstream Christian denominations to engage in dialog with persons of other faiths.[15] Nevertheless, some apologists have argued for the usage of the term, stating that it does not come from a disrespectful perspective, but is similar to using the term orthodox for devout believers.[16]

Moreover, some translations of the Bible, such as the Authorized Version, which is still in vogue today, employ the word infidel, while others supplant the term with nonbeliever; the term is found in two places:

And what concord hath Christ with Belial? Or what part hath he that believeth with an infidel? —2 Corinthians 6:15 KJV
But if any provide not for his own, and specially for those of his own house, he hath denied the faith, and is worse than an infidel. —1 Timothy 5:8 KJV