Had a grudge
To kill him.
But she could not.”
ἡ δὲ Ἡρῳδιὰς ἐνεῖχεν αὐτῷ καὶ ἤθελεν αὐτὸν ἀποκτεῖναι, καὶ οὐκ ἠδύνατο·
This is a unique verse of Mark, who said that Herodias had a grudge against John (ἡ δὲ Ἡρῳδιὰς ἐνεῖχεν αὐτῷ). She wanted or wished to kill him (καὶ ἤθελεν αὐτὸν ἀποκτεῖναι), but she was not able to or could not kill him (καὶ οὐκ ἠδύνατο). In other words, the wife of Herod was really angry at John the Baptist for what he had said about her and her marriage to King Herod.