/tə ˈdu ˈfeɪəlti/ – Phrase
Definition: thề trung thành.
A more thorough explanation: To “do fealty” is a legal term that refers to the act of making a formal oath of loyalty and allegiance to a feudal lord or superior. This act typically involves a vassal or subordinate swearing an oath of fealty to their lord, promising to serve and support them in exchange for protection and other benefits.
Example: The vassal was required to do fealty to his lord by swearing an oath of loyalty and allegiance.