A more thorough explanation:

Definition: A disturber is a person who interferes with a patron's right of advowson, which is the right to appoint a clerk to a benefice. It is also known as an impeditor.

Example: John was appointed as the clerk to a benefice by the patron of the church. However, Peter, who was not authorized to do so, interfered with the appointment and tried to appoint someone else. Peter is a disturber or impeditor.

The example illustrates how a person who interferes with the right of advowson of a patron is called a disturber or impeditor.