Greek: αντιχριστος [antichristos] (Noun masculine). From αντι [anti] and χριστος [christos]: "against Christ", "in the place of Christ". Antichrist.

αντιχριστος [antichristos] appears 5 times in the NT:

(1, 2) 1 John 2: 18
Little children, it is the last time: and as ye have heard that antichrist¹ shall come, even now are there many antichrists²; whereby we know that it is the last time. - ¹αντιχριστος [antichristos] Nom. sing. / ²αντιχριστοι [antichristoi] Nom. pl.

(3) 1 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. - ο αντιχριστος [ho antichristos] Nom. sing. ("He is antichrist" - ουτος εστιν ο αντιχριστος [houtos estin ho antichristos] Lit: "this is the antichrist").

(4) 1 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 it in the world. - του αντιχριστου [tou antichristou] Gen. sing.

(5) 2 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. - ο αντιχριστος [ho antichristos] Nom. sing.