Definition of "abhominable"

This is abhominable, which he [Don Armado] would call abominable.

1597, Shakespeare, Love's Labour's Lost, act 5, scene I

[...] your Lordship [is] twice guilty of treachery both in withholding the dominion of Narnia from the said Caspian and in the most abhominable, —don’t forget to spell it with an H, Doctor— bloody, and unnatural murder of your kindly lord and brother King Caspian Ninth of that name.

1951, w:C. S. Lewis, Prince Caspian, chapter XIII