A more thorough explanation:

ALIENATIO FEUDI

Alienatio feudi is a legal term in Latin that refers to the transfer or disposition of a feudal right.

One example of alienatio feudi is when a lord grants a vassal the right to use a piece of land for farming. The lord can later transfer this right to another vassal or sell it to a third party. Another example is when a vassal pledges loyalty and military service to a lord in exchange for protection and the right to use a piece of land. The vassal can later transfer this right to his heir or sell it to another vassal.

These examples illustrate how feudal rights were transferable and could be bought and sold like property. Alienatio feudi was an important aspect of feudalism, as it allowed lords and vassals to negotiate and exchange rights and obligations.