These are the only places that the word antichrist is mentioned.
1 John 2:18
Dear children, this is the last hour; and as you have heard that the antichrist is coming, even now many antichrists have come. This is how we know it is the last hour.
1 John 2:22
Who is the liar? It is whoever denies that Jesus is the Christ. Such a person is the antichrist —denying the Father and the Son.
1 John 4:3
but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist , which you have heard is coming and even now is already in the world.
2 John 1:7
I say this because many deceivers, who do not acknowledge Jesus Christ as coming in the flesh, have gone out into the world. Any such person is the deceiver and the antichrist .