WordWeb Online

1. Stubbornly resistant to authority or control
   "a fractious animal that would not submit to the harness";
   - refractory, recalcitrant, incalcitrant [non-standard]
    
2. Easily irritated or annoyed
   "an incorrigibly fractious young man";
   - cranky [informal], irritable, nettlesome, peevish, peckish [N. Amer, informal], pettish, petulant, scratchy, testy, tetchy, techy, pouty, narky [Brit, slang]
    
3. Unpredictably difficult in operation; likely to be troublesome
   "rockets were much too fractious to be tested near thickly populated areas"; "fractious components of a communication system"

See also: difficult, disobedient, hard, ill-natured