protector

noun7

1. •
   Someone who protects or guards, by assignment or on their own initiative.

   • I stand before you in the spirit of pure public service — not as a protector of the status quo, but as an agent of change. — 2005
2. •
   A headmate who primarily fronts, or otherwise protects the system, in situations where the system is at risk of psychological harm.
3. •
   A device or mechanism which is designed to protect.
4. •
   One who prevents interference.
5. •
   A state or other subject under international law, exercising a protectorate over another subject in international law.
6. •
   (UK, historical) One having the care of the kingdom during the king's minority; a regent.

   • My Lord Protector, ’tis his Highnes pleasure, You do prepare to ride vnto S. Albons, / Where as the King and Queene do mean to Hawke. — 1591
7. •
   A cardinal, from one of the more considerable Roman Catholic nations, who looks after the interests of his people at Rome; also, a cardinal who has the same relation to a college, religious order, etc.