guard·i·an 
(gärdē-ən)
(gärdē-ən)n.
1. One that guards, watches over, or protects.
2. Law
a. One who is legally responsible for the care and management of the person or property of an incompetent or minor.
b. See guardian ad litem.
3. A superior in a Franciscan monastery.
[Middle English gardein, from Anglo-Norman, from Old French gardien, from alteration of gardenc, from garder, to guard; see GUARD.]
guardi·an·ship′ n.