Feudal labourer (4)
I believe the answer is:
serf
'feudal labourer' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for serf that I've seen before include "'In the Middle Ages, a person owned by a feudal lord (4)'" , "Medieval person bound to a feudal lord" , "Feudal peasant" , "Servant, vassal" , "Feudal labourer" .)