Stemming from the Latin word "fidelitas," the noun fealty is related to "fidelity," and is another way of saying "loyalty" or "faithfulness."
Most school kids pledge their fealty, or allegiance, to the United States of America every morning in homeroom. But if you think fealty sounds like a word King Arthur would use, you're right: It's really an outdated term that primarily describes a vassal's sworn allegiance to a feudal lord.
