noun

1. in the Middle Ages, a person who held land under the feudal system, doing homage and pledging fealty to an overlord, and performing military or other duties in return for his protection; feudal tenant
2. a subordinate, subject, servant, slave, etc.

Etymology: OFr < ML vassalus, manservant, extension of vassus, servant < Celt: for IE base see valet

adjective

1. of or like a vassal; dependent, servile, etc.
2. being a vassal