steadfastness vs loyalty

steadfastness and loyalty both are nouns.

Word	Noun	Adjective	Verb	Adverb
steadfastness	Yes	No	No	No
loyalty	Yes	No	No	No

As nouns, loyalty is a hypernym of steadfastness; that is, loyalty is a word with a broader meaning than steadfastness:

Other hypernyms of steadfastness include trueness.

steadfastness (noun)	loyalty (noun)
loyalty in the face of trouble and difficulty	the act of binding yourself (intellectually or emotionally) to a course of action
steadfast resolution	the quality of being loyal
	feelings of allegiance