1. Supplying or being a final or conclusive settlement
   "a definitive verdict";
   - determinate
    
2. Of recognized authority or excellence
   "the definitive work on Greece";
   - authoritative
    
3. Clearly defined or formulated
   "the plain and definitive language of the laws";
   - unequivocal

See also: conclusive, explicit, expressed, standard

Encyclopedia: Definitive