antagonistic
     adj 1: indicating opposition or resistance [syn: {counter}]
     2: characterized by antagonism or antipathy; "slaves
        antagonistic to their masters"; "antipathetic factions
        within the party" [syn: {antipathetic}, {antipathetical}]
     3: arousing animosity or hostility; "his antagonizing
        brusqueness"; "Europe was antagonistic to the Unites
        States" [ant: {conciliatory}]
     4: used especially of drugs or muscles that counteract or
        neutralize each other's effect [syn: {incompatible}] [ant:
         {synergistic}]
     5: opposing or neutralizing or mitigating an effect by contrary
        action [syn: {counteractive}] [ant: {active}]
     6: incapable of harmonious association
Source: WordNet® 2.0