Sir Knight or Sir (name)
They would be a serf.
A peasant worked the land, but had freedom. A serf was bound to the land that they worked. They would live on the manor of a noble and work the land in exchange for food and protection.
Peasant/serf
Peasant
A peasant who is bound to land is a serf, while a fief is an estate granted to a vassal.
A peasant who was bound to a manor was a serf.
Peasant
peasant or serf, or lady
A serf or peasant
The peasants
A serf could quit there job, but they would have to escape and remain away from there lords land for one year. Then they would be free and were a average day peasant's.
Your question is not entirely correct in its premise; a serf is not a slave and does not have an owner. A serf is a subject of a land owner whom the serf would address as lord.