Final answer:
A serf was an individual in the feudal system who could not leave the land without the noble's permission, performing labor in exchange for protection and the right to live on the lord's land.
Step-by-step explanation:
The person who could not leave the land without the permission of the noble was known as a serf. These individuals were the agricultural laborers within the feudal system and were bound to the land they worked on, which was owned by a lord. As serfs, they owed service to their lord, including labor and goods, and faced significant limitations, such as not being allowed to marry or relocate without their lord's consent.
The feudal society was a structured hierarchy with interdependent relationships between lords, knights, vassals, and serfs. Serfs were the lowest social class but crucial to the subsistence economy of the feudal era, working the land to produce food for the populace and the surplus went to the lord or the Church as part of a tithe.