1.
Holiness is the state or quality of being holy.
We were immediately struck by this city’s ~.
N-UNCOUNT: usu with supp
2.
You say Your Holiness or His Holiness when you address or refer respectfully to the Pope or to leaders of some other religions.
The President received His Holiness at the White House.
N-VOC: poss N; PRON: poss PRON politeness