Then it would be better to show their error from the Biblical record, it is easy enough to do. Why invent a term that incorperates Mary in the mix. This just further confuses things to the "sheep". The cure is almost as bad as the disease. Step back and look at it as if you were hearing it for the first time" "Mary, the mother of God". If you are fair and honest you can see the problem with that statement. It implies that Jesus, who is God, did not exist before his human birth and that God himself sprang from Mary, rather than Mary being a created being, made by God. IOW, as with the other RC Mariology, it puts the emphasis in the wrong place.
Indeed it is a confusing term unless properly understood. I don't know if the Greek term has the same ambiguities.
SD