According to Merriam webster, "loyalty" is the alteration of middle English, it was first used in the 15th century.
According to me being loyal is a lot of different things. Being loyal is being faithful and committed to someone or something. It is being dedicated and obedient. But most importantly it is being honest to others and yourself.
To be loyal is promising you will have the dishes done by Saturday and finishing them on Friday. To be loyal is finishing your homework on time. To be loyal is to be honest with yourself and others.
According to me being loyal is always keeping your word. Being loyal is to not go behind someone's back when you really want too. Someone who is loyal is someone you can always count on, someone who would never get be caught lying. Someone you can always trust to keep your secrets.
Loyalty is telling the truth, even though the truth may hurt someone. Loyalty is putting others before you all time.
Loyalty is not cheating. Loyalty is not giving up. Loyalty is not lying to others. Loyalty is not inconsistently making the same mistakes. Loyalty is not being indifferent when times get hard.