[1 John 2:18-24 NASB95]
18 Children, it is the last hour; and just as you heard that antichrist is coming, even now many antichrists have appeared; from this we know that it is the last hour. 19 They went out from us, but they were not [really] of us; for if they had been of us, they would have remained with us; but [they went out,] so that it would be shown that they all are not of us. 20 But you have an anointing from the Holy One, and you all know. 21 I have not written to you because you do not know the truth, but because you do know it, and because no lie is of the truth. 22 Who is the liar but the one who denies that Jesus is the Christ? This is the antichrist, the one who denies the Father and the Son. 23 Whoever denies the Son does not have the Father; the one who confesses the Son has the Father also. 24 As for you, let that abide in you which you heard from the beginning. If what you heard from the beginning abides in you, you also will abide in the Son and in the Father.
[1 John 4:1-6 NASB95]
1 Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. 2 By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God; 3 and every spirit that does not confess Jesus is not from God; this is the [spirit] of the antichrist, of which you have heard that it is coming, and now it is already in the world. 4 You are from God, little children, and have overcome them; because greater is He who is in you than he who is in the world. 5 They are from the world; therefore they speak [as] from the world, and the world listens to them. 6 We are from God; he who knows God listens to us; he who is not from God does not listen to us. By this we know the spirit of truth and the spirit of error.
[2 John 1:7-11 NASB95]
7 For many deceivers have gone out into the world, those who do not acknowledge Jesus Christ [as] coming in the flesh. This is the deceiver and the antichrist. 8 Watch yourselves, that you do not lose what we have accomplished, but that you may receive a full reward. 9 Anyone who goes too far and does not abide in the teaching of Christ, does not have God; the one who abides in the teaching, he has both the Father and the Son. 10 If anyone comes to you and does not bring this teaching, do not receive him into [your] house, and do not give him a greeting; 11 for the one who gives him a greeting participates in his evil deeds.
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I think people are sloppy with the use of the term “Antichrist” and should reserve it for when it is appropriate only.