This word began to appear in Latin documents in the late 11c as a synonym for villanus, i.e. a *villein. Its use suggests a wish to abandon the old word with its negative connotations of a person unfree. The Latin term for this person's status was bondagium, replacing villanagium. Bondacra was the acre of land held by a bondus.
Cf. Bondsman
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.