Who is not a guardian according to Section 4 of the Hindu Minority and Guardianship Act ?

Section 4(b) of the Hindu Minority and Guardianship Act, 1956 says "guardian" includes a natural guardian, a guardian appointed by the will of the minor's father or mother (testamentary guardian), a guardian appointed or declared by a court, and a person empowered to act as such under any enactment relating to a court of wards. An ad hoc guardian is not among them, and section 11 bars a de facto guardian from dealing with the minor's property.