The noun enmity means a feeling of hatred into someone that usually lasts for a long time.
Synonyms are antagonism, animus, alienation, or loathing.
The word origins from Old French (14th century) enemite, variant of enemistié meaning “enmity, hostile act, aversion” (Modern French inimité). It also sources from Vulgar Latin inimicitatem (nominative inimicitas), and Latin inimicitia meaning “enmity, hostility”, usually plural, from inimicus meaning “enemy”.
Cain felt enmity toward his brother Abel.
His connection with the controlling elites brought upon him the enmity of the common people.
It is not good to harbor lifelong enmity toward your family.