Resentimiento vs. rencor

While both 'resentimiento' and 'rencor' are Spanish words that can be translated as 'resentment' in English, they have subtle differences in usage and intensity.

Resentimiento

'Resentimiento' refers to a feeling of indignation or displeasure at something considered unjust or offensive. It's often a more general and less intense form of resentment.
Sintió resentimiento cuando no lo invitaron a la fiesta.
(He felt resentment when he wasn't invited to the party.)
El resentimiento por el comentario de su jefe duró unos días.
(The resentment over his boss's comment lasted a few days.)

Rencor

'Rencor' indicates a deeper, more lasting feeling of ill will or hatred. It's a more intense and enduring form of resentment, often implying a desire for revenge.
Después de años, aún guardaba rencor por la traición de su amigo.
(After years, he still harbored resentment for his friend's betrayal.)
El rencor entre las dos familias se mantuvo por generaciones.
(The resentment between the two families lasted for generations.)

Summary

While 'resentimiento' describes a more general and often temporary feeling of displeasure, 'rencor' implies a deeper, more intense, and long-lasting negative emotion, often associated with a desire for revenge. 'Resentimiento' might fade with time, but 'rencor' tends to persist and can be more difficult to overcome.