1 John 2:22 τίς ἐστιν ὁ ψεύστης εἰ μὴ ὁ ἀρνούμενος ὅτι Ἰησοῦς οὐκ ἔστιν ὁ Χριστός; οὗτός ἐστιν ὁ ἀντίχριστος ὁ ἀρνούμενος τὸν πατέρα καὶ τὸν υἱόν.
Who is the liar but he who denies that Jesus is the Christ? This is the Antichrist, he who denies the Father and the Son.
Noun: Nominative Singular Masculine

2 John 1:7 ὅτι πολλοὶ πλάνοι ἐξῆλθον εἰς τὸν κόσμον, οἱ μὴ ὁμολογοῦντες Ἰησοῦν Χριστὸν ἐρχόμενον ἐν σαρκί· οὗτός ἐστιν ὁ πλάνος καὶ ὁ ἀντίχριστος.
For many deceivers have gone out into the world, those who don't confess that Jesus Christ came in the flesh. This is the deceiver and the Antichrist.
Noun: Nominative Singular Masculine