The Bible prophesies an end-time figure who opposes Christ—the Antichrist—but the meaning of the term antichrists encompasses more than just the end time. This term literally means "against Christ" and is variously defined as "adversary of Christ" or "opponent of Christ" and as a title or proper name for a specific individual who opposes and claims to be Christ.
The Greek-English Lexicon of the New Testament Based on Semantic Domains by Louw and Nida offers a more comprehensive definition:
"The term . . . appears to have become increasingly equivalent to a proper name as the personification of all that was opposed to and contrary to the role and ministry of Christ."
According to the apostle John's writing, there is a spirit of antichrist, which is a spirit of opposition to the identity of Christ. Specifically, he was writing to warn of the dualistic heresy that denied that Christ lived as a physical human being (1 John 4:3 1 John 4:3And every spirit that confesses not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof you have heard that it should come; and even now already is it in the world.
American King James Version×; 2 John 1:7 2 John 1:7For many deceivers are entered into the world, who confess not that Jesus Christ is come in the flesh. This is a deceiver and an antichrist.
American King James Version×).
The Bible does not reveal specifically who the Antichrist is, speaking instead of his corrupt teachings.
In the first century, most people of Jewish background anticipated a Messiah who would come to the earth as a conquering king to establish the Kingdom of God. But they failed to understand that He would first come as a man who would become the sacrifice for the sins of mankind, and they refused to accept Jesus as the Messiah. (The word Messiah is the Hebrew counterpart to the Greek word Christ.) Their doctrine was an example of a spirit of antichrist.
Today, many members of mainstream Christianity make the opposite mistake from the one that the Jews made by accepting that Christ became the perfect sacrifice for sin but denying His coming to the earth as a conquering king. So ironically, even that traditional Christian doctrine can be classified as "antichrist."
End-time prophecies show that religious people—including professing Christians deceived into accepting a counterfeit Christianity—will oppose many of the teachings of Christ. In that real sense, even today, many professing Christians actually have been deceived by a spirit of antichrist.
The Bible does not reveal specifically who the Antichrist is, speaking instead of his corrupt teachings. In 2 Thessalonians 2, Paul prophesied of a "man of sin," a liar and deceiver whose natural abilities Satan enhances by supernatural power in order to confuse people in the end time. In addition, Christ inspired John to write of a "false prophet" to come at the end time (Revelation 13:1-18 Revelation 13:1-18  And I stood on the sand of the sea, and saw a beast rise up out of the sea, having seven heads and ten horns, and on his horns ten crowns, and on his heads the name of blasphemy.
 And the beast which I saw was like to a leopard, and his feet were as the feet of a bear, and his mouth as the mouth of a lion: and the dragon gave him his power, and his seat, and great authority.
 And I saw one of his heads as it were wounded to death; and his deadly wound was healed: and all the world wondered after the beast.
 And they worshipped the dragon which gave power to the beast: and they worshipped the beast, saying, Who is like to the beast? who is able to make war with him?
 And there was given to him a mouth speaking great things and blasphemies; and power was given to him to continue forty and two months.
 And he opened his mouth in blasphemy against God, to blaspheme his name, and his tabernacle, and them that dwell in heaven.
 And it was given to him to make war with the saints, and to overcome them: and power was given him over all kindreds, and tongues, and nations.
 And all that dwell on the earth shall worship him, whose names are not written in the book of life of the Lamb slain from the foundation of the world.
 If any man have an ear, let him hear.
 He that leads into captivity shall go into captivity: he that kills with the sword must be killed with the sword. Here is the patience and the faith of the saints.
 And I beheld another beast coming up out of the earth; and he had two horns like a lamb, and he spoke as a dragon.
 And he excercises all the power of the first beast before him, and causes the earth and them which dwell therein to worship the first beast, whose deadly wound was healed.
 And he does great wonders, so that he makes fire come down from heaven on the earth in the sight of men,
 And deceives them that dwell on the earth by the means of those miracles which he had power to do in the sight of the beast; saying to them that dwell on the earth, that they should make an image to the beast, which had the wound by a sword, and did live.
 And he had power to give life to the image of the beast, that the image of the beast should both speak, and cause that as many as would not worship the image of the beast should be killed.
 And he causes all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads:
 And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.
 Here is wisdom. Let him that has understanding count the number of the beast: for it is the number of a man; and his number is Six hundred three score and six.
American King James Version×; Revelation 16:13 Revelation 16:13And I saw three unclean spirits like frogs come out of the mouth of the dragon, and out of the mouth of the beast, and out of the mouth of the false prophet.
American King James Version×; Revelation 19:20 Revelation 19:20And the beast was taken, and with him the false prophet that worked miracles before him, with which he deceived them that had received the mark of the beast, and them that worshipped his image. These both were cast alive into a lake of fire burning with brimstone.
American King James Version×).
Finally, note how the prophecy describes a great religious leader of the end time: "He had two horns like a lamb and spoke like a dragon" (Revelation 13:11 Revelation 13:11And I beheld another beast coming up out of the earth; and he had two horns like a lamb, and he spoke as a dragon.
American King James Version×). That is to say, he takes on the image of (or imitates) Jesus Christ (the Lamb of God), but is empowered by Satan. Historically, a counterfeit version of Christianity fulfills the types we read of in the prophecies of Revelation.