What is means
1 a: the fidelity of a vassal or feudal tenant to his lord
b: the obligation of such fidelity
The vassal vowed fealty to the king.
2: intense fidelity
the fealty of country music fans to their favorite stars
—Nicholas Dawidoff
Fealty in context
He swore fealty to the king.
as much as I wanted to back my friend up, my fealty to the truth was greater, and I could not lie for him
Did you know?
In The Use of Law, published posthumously in 1629, Francis Bacon wrote, “Fealty is to take an oath upon a book, that he will be a faithful Tenant to the King.” That’s a pretty accurate summary of the early meaning of fealty. Early forms of the term were used in Middle English in the early 14th century, when they specifically designated the loyalty of a vassal to a lord.
Eventually, the meaning of the word broadened. Fealty can be paid to a country, a principle, or a leader of any kind, though the synonyms fidelity and loyalty are more commonly used. Fealty comes from the Anglo-French word feelté, or fealté, which comes from the Latin noun fidēlitās, meaning “fidelity.” These words come ultimately from fidēs, the Latin word for “faith.”
www.merriam-webster.com