A more thorough explanation:

Definition: Feudary is another term for feudatory, which refers to a vassal who owes feudal allegiance to a lord or the grantee of a feud who held an estate by feudal service.

Example: In medieval Europe, a feudary was a person who held land from a lord in exchange for military service or other obligations. For example, a knight might be a feudary of a king, and in return for his loyalty and service, he would receive a fief or a piece of land to govern.

Explanation: The example illustrates how a feudary was a vassal who owed allegiance to a lord and held an estate by feudal service. The knight in the example was a feudary of the king, and he was obligated to provide military service in exchange for his fief. This system of feudalism was prevalent in medieval Europe and was based on the exchange of land for loyalty and service.