Unholy Authority is an Ascendancy passive skill for the Occultist. It raises the additional curse limit by one and enables your hexes to affect Hexproof enemies.
Hexproof is a keyword and modifier that causes the monsters with it to be unaffected by Hex curses, but can be bypassed under certain conditions. Hexproof doesn’t affect Mark curses.
Hexproof is not curse immunity, which prevents both Hexes and Marks from being applied at all.
Hexes on Hexproof enemies can still accumulate Doom, but only if the enemies are affected by the hex.
The player character can have this buff by stealing it from monster when using Headhunter or Inspired Learning.
The Occultist’s Malediction Notable Ascendancy Passive Skill has been renamed to Unholy Authority. It no longer provides 15% increased Effect of your Curses, or “Enemies you curse have Malediction.” It now provides “Your Hexes can affect Hexproof Enemies.”