Wikipedia
A smerd is a free and later feudal-dependent peasant in the medieval Slavic states of East Europe. Sources from the 11th and 12th centuries mention smerds’ presence in Kievan Rus' (e.g. Russkaya Pravda) and Poland as the smardones.
In Kievan Rus', the smerds were peasants who had been gradually losing their freedom (partially or completely) and whose legal status had differed from group to group. Unlike the slaves, they had their own property and had to pay fines for their delinquencies. Legally, the smerds never possessed full rights; the killing of a smerd was punished by the same fine as the killing of a kholop (status similar to a slave). The property of the deceased was inherited by the knyaz (prince). The Russkaya Pravda forbade torturing the smerds during court examination without the consent of the knyaz.
During the 12th and 13th centuries, the smerds were mentioned in a number of sources narrating the events in Halych-Volynia and Novgorod. It appears that during this period the term "smerd" encompassed the whole rural population of a given region. Sources of the 14th and 15th centuries refer to the smerds of Novgorod and Pskov as peasants- proprietors, who possessed lands collectively (communes) or individually and had the right to freely alienate their own allotments. However, their personal freedom was limited: they were forbidden to seek for a new master or princely patronage. The knyaz could not accept complaints from the smerds on their master. Also, the smerds had required to provide labor services and pay tribute (dan') to the benefit of the city as a collective feudal master.