Direct opposition or conflict between two things; the state of being antagonistic or fundamentally opposed.
From Greek anti- 'against' + agon 'struggle, contest'. This is a parallel formation to 'antagonism' (with the -ism suffix instead), both referring to fundamental opposition. The word is archaic in modern English.
Antagony is almost obsolete, having been replaced by 'antagonism,' but it appears in older philosophical texts discussing fundamental oppositions—like the antagony between order and chaos. Watching words become extinct is one of the best ways to understand how language evolves.
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