A rent-paying tenant who was not obliged to perform week-work but could be called upon for *boon work. He might be obliged to do some mowing or lend his plough. A money rent was known as censaria. In the early 12c, rent could be 1s 6d per *bovata. [< Lat. censura = assess < census = tax, payment]
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.