WordWeb Online

1. Indicating opposition or resistance
   - counter
    
2. Characterized by antagonism or antipathy
   "slaves antagonistic to their masters";
   - antipathetic, antipathetical
    
3. Incapable of harmonious association
    
4. Arousing animosity or hostility
   "his antagonistic brusqueness"; "Europe was antagonistic to the United States"
    
5. Used especially of drugs or muscles that counteract or neutralize each other's effect
   - incompatible

See also: alienating, antacid, antiphlogistic, hostile, incompatible, negative

Antonym: conciliative

Encyclopedia: Antagonistic