Here is a definition most Reformers would have used for the Antichirst.
The Term Antichrist: "We shall not go far afield in this discussion: nor is it in the least necessary to do so. The materials for a right decision on the question before us lie close at hand. The Apostle John, speaking of the great apostacy to arise in Christendom, calls it the Antichrist. And the Pope has taken to himself, as the name that best describes his office, the title Vicar of Christ. All we shall ask as the basis of our argument are these two accepted facts, namely, that John styles the apostacy, the Antichrist, and that the head of the Roman system styles himself Christs Vicar.
The Papacy holds in its name the key of its meaning. We shall make use of that key in unlocking its mystery and true character. The Papacy cannot complain though weadopt this line of interpretation. We do nothing more than use the key it has put into our hands. The Apostle John, we have said, speaking of the apostacy, the coming of which he predicts, styles it the Antichrist. And we have also said that the Papacy, speaking through its representative and head, calls itself the Vicar of Christ. The first, Antichrist, is a Greek word, the second, Vicar, is an English word; but the two are in reality one, for both words have the same meaning. Antichrist translated into English is vice-Christ, or Vicar of Christ; and Vicar of Christ, rendered into Greek is Antichrist Antichristos.
If we can establish this and the ordinary use of the word by those to whom the Greek was a vernacular, isdecisive on the point we shall have no difficulty in showing that this is the meaning of the word Antichrist, even a Vice-Christ. And if so, then every time the Pope claims to be the Vicar of Christ, he pleads at the bar of the world that he is the Antichrist. Moreover, this will clear our way and simplify our discussion. For, let it be noted, if Antichrist signifies a Vice-Christ that is, one who comes in the room of Christ deception, dissimulation, counterfeit, must be an essential element in his character. In whatever persons or systems that fundamental characteristic is lacking, we fail to find the Antichrist, whatever may be their general opposition to Christ and to Christianity, or whatever other features of the Antichrist they may bear. They may have every othercharacteristic by which prophecy had described this noted adversary of Christ and his gospel, yet, lacking thisfundamental one, their claim to this pre-eminently evil distinction cannot be admitted. This enables us to dismisssummarily and at once a host of Antichrists which have been conjured up by persons who have drawn upon their imagination, rather than followed any sound principle of prophetic interpretation. The cause of the papacy is served by the false glosses and mistaken interpretations of Scripture which interpose a pseudo-antichrist betwixt it and Prophecy, which unfolds against it so black a record, and suspends above it so terrible a doom.
We shall suppose that an atheist or an infidel has been put to the bar to answer to a charge of being the Antichrist. He has manifested a Satanic malignity against the Gospel, and has laboured to the utmost of his power to destroy it. He has blasphemed God, execrated Christ, and derided, vilified, and persecuted all who profess His name, and on these grounds he has been assumed to be the Antichrist. The case is no imaginary one. Atheists and scoffers in former ages, Voltaire and Paine in later times, Communists and Pantheists in our own day, have all been arraigned as the Antichrist. Well, let us suppose that one or other of these notoriously wicked personages or systems has been put to the bar, on the charge of being theadversary predicted by John. Who are you? says the judge. Are you aVice-Christ? So you make a profession ofChristianity, and under that pretext seek to undermine and destroy it? No, replies theaccused. I am no counterfeit. Christ and His Gospel I hate; but I am an open enemy, I fight under no mask. Turning tothe likeness drawn by Paul and John of Christs great rival and opponent, and finding the outstanding and essential feature in the portrait absent in the accused, the judge would be constrained to say, I do not find the charge proven. Go your way; you are not the Antichrist.
Mohammedanism comes nearer than any other of the opposing systems to the Antichrist of the Bible; yet it falls a long way short of it. Mohamet did not disavow the mission of Jesus; on the contrary, he professed to hold Him in honour as a prophet. And in much the same way do His followers still feel towards Christ. But Islam does not profess to be an imitation of Christianity. Any counterfeit that can be discovered in Mohammedanism is partial and shadowy when placed alongside the bold, sharp-cut counterfeit of Romanism. It requires a violent stretch of imagination to accept Mohammedanism, or, indeed, any other known ism, as a Vice-Christ. Of all systems that ever were on the earth, or are now upon it, Romanism alone meets all the requirements of prophecy, and exhibits all the features of the Vice-Christ; and it does so with a completeness and a truthfulness which enable the man who permits himself to be guided by the statements of the Word of God on the one hand, and the facts of history on the other, to say at once, "This is the Antichrist."
What we have said is meant to indicate the lines on which our demonstration will proceed. We must trace the parallelism betwixt their respective chiefs, Christ and the Pope, along the entire line of their career. In this parallelism lies the essence of Antichristianism, and of course the strength of our argument. It is this counterfeit, so exact and complete, which has misled the world into the belief that this is Christianity, to the waste of ages not a few, the unsettling and overthrow of kingdoms, the stunting of the human understanding, and the loss of millions of immortal souls." J. A. Wylie