Qadosh

Holy is what has been set apart for one use only — not what is morally better.

The primary idea is cutting, separation: a temple pot is qadosh not because it is virtuous but because it serves nothing else. Applied to people, holiness stops being moral performance and becomes exclusive belonging. Isaiah's trisagion (“holy, holy, holy”) uses threefold repetition, the Hebrew superlative, which has no other way of saying “to the highest degree”.