IPA: /ˌæntæɡəˈnɪzəm/
KK: /æntæɡənɪzəm/
A situation where there is hostility or active opposition between people or groups.
The antagonism between the two rival teams was evident during the match.
Antagonism is formed from "anti-" (meaning against) and "agon" (from Greek "agōn", meaning contest or struggle). The word describes a state of opposition or conflict, particularly in a competitive context.
Think of 'against' ('anti-') in a 'contest' ('agon') — that's why antagonism means being in opposition or conflict.