The word “kecharitōmenē” appears in the Bible in Luke 1:28, where the angel greets Mary:
“Greetings, you who are highly favored.”
In the original Greek text, it says:
χαῖρε, κεχαριτωμένη
(chaire, kecharitōmenē)
“Kecharitōmenē” literally means:
“The one who has been completely and permanently endowed with grace.”
It is a unique word in the Bible—only Mary is called this.
It means: God has completely filled Mary with his grace, not just once, but forever.
That is why the Church believes: Mary was without sin even before the birth of Jesus—completely filled by God.