Loyal means staying true to your friends, your side or your promises. A loyal friend, loyal to the company, fiercely loyal.
It implies staying when leaving would be easier, which is what separates it from merely friendly. The construction is loyal to. Loyalty is the noun, and loyalty card is the commercial use — a card that rewards you for shopping in the same place. Note loyalist, which in political contexts means somebody supporting an existing government or union, and disloyal, which is a serious accusation in most settings.
1adjectiveloyalStaying true to people or promises.
“He stayed loyal when it cost him everything.”
loyal is a quality of faithfulness.
Also accepted in games: faithful
Old French loial comes from Latin legalis, lawful — the same word that gives English legal. Loyalty and legality are the same idea borrowed twice, once through French with the sense of faithfulness and once from Latin directly.
Middle French
loyal
English, today
loyal
Borrowed from Middle French loyal. Middle French loyal, from Old French loial, leial, leal, from Latin lēgālis. a doublet of legal and leal.
Etymology from Wiktionary, CC BY-SA