The noun antagonism means the feeling of strong dislike or opposition to someone.

Synonyms are animosity, disagreement, hatred, or resistance.

The word origins from French (1797) antagonisme meaning “state of being mutually opposed; opposition between two things or against something”, and directly from Late Greek antagonisma, noun of action from antagonizesthai meaning “to struggle against, oppose, be a rival”. It comes from anti meaning “against’” plus agonizesthai meaning “to contend for a prize”.

The antagonism of the two families was even more intense.

The prime minister made a harsh rule that aroused great antagonism in citizens.

The housemates show no antagonism between each other.