The word antichrist refers to those who do not confess that Jesus Christ came in the flesh.
All text taken from the King James Bible
II John :7 - For 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.
I John 4:3 - And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is in the world.
I John 2:22 - Who is a liar but he that denieth that Jesus is the Christ? He is antichrist, that denieth the Father and the Son.
I John 2:18 - Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.
II Thes.2:3 - Let no man deceive you by any means: for that day shall not come, except there came a falling away first, and that man of sin be revealed, the son of perdition;
The son of perdition is the devil, Satan, wicked one, or the serpent, they are all the same thing. See - Day of the Lord Also see -Parable of the Kingdom and Sower Scriptural Definitions