1. Having or showing a ready disposition to fight
   "a combative impulse";
   - battleful [archaic], bellicose
    
2. Inclined or showing an inclination to dispute or disagree, even to engage in lawsuits
   "a style described as abrasive and combative";
   - contentious, disputatious, disputative, litigious
    
3. Striving to overcome in argument
   "a dialectical and combative approach";
   - agonistic, agonistical

See also: adversarial, aggressive, argumentative, competitive, competitory

Encyclopedia: Combative