Lealtad vs. fidelidad

While 'lealtad' and 'fidelidad' in Spanish both translate to 'loyalty' or 'fidelity' in English, they have slightly different connotations that distinguish themselves from each other in use.

Lealtad

'Lealtad' is a term that specifically refers to loyalty in terms of faithfulness to a particular person, cause, or duty. It emphasizes the sincerity and commitment from the individual as a personal attribute.
El soldado mostró lealtad a su país al defenderlo en tiempo de guerra.
(The soldier showed loyalty to his country by defending it during wartime.)
Aprecio tu lealtad hacia nuestra amistad durante todos estos años.
(I appreciate your loyalty towards our friendship over all these years.)
La lealtad de un perro hacia su dueño es algo realmente notable.
(The loyalty of a dog towards its owner is really remarkable.)

Fidelidad

'Fidelidad', on the other hand, tends to be used more in the context of maintaining faithfulness within a relationship, such as a romantic partnership. It alludes more towards the monotheistic adherence or devotion to someone, often referencing fidelity or faithfulness in marriage or relationships.
Juré fidelidad a mi esposa el día de nuestro matrimonio.
(I vowed fidelity to my wife on the day of our marriage.)
La fidelidad es un pilar importante en cualquier relación amorosa.
(Fidelity is an important pillar in any loving relationship.)
El príncipe prometió fidelidad al rey y a la reina.
(The prince vowed fidelity to the king and queen.)

Summary

'Lealtad' and 'fidelidad' both reference loyalty or faithfulness but they are used differently based on context. While 'lealtad' is broader and can refer to loyalty to a cause or duty and focuses more on personal attribute, 'fidelidad' has a narrower scope and is all about loyalty within relationships, often in terms of monogamy.