means The quality of being holy — sacred, morally pure, or set apart for the divine — and also a title of reverence (as in His Holiness).

from From Old English hālignes, built on hālig 'holy,' which traces back to a Germanic root meaning 'whole, sound, uninjured' — a cousin of 'hale' and 'whole.' The idea of holiness thus grew from wholeness: to be holy was to be complete, intact, unbroken — set apart not by damage but by perfection. The '-ness' suffix simply turns the adjective into the abstract state of the thing.