Synonyms for Antagonistic (same or very similar meaning)
WordNet sense 1 (indicating opposition or resistance):
counter
WordNet sense 2 (characterized by antagonism or antipathy):
antipathetic, antipathetical
WordNet sense 3 (characterized by enmity or ill will):
hostile
WordNet sense 4 (not compatible):
incompatible
From the ODE community, based on WordNet
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