neutral in WordNet English dictionary

1. having no hue
   "neutral colors like black or white"
   achromatic  neutral 
   
2. having no net electric charge
   neutral  electroneutral 
   
3. having no personal preference
   "impersonal criticism"; "a neutral observer"
   impersonal  neutral 
   
4. having only a limited ability to react chemically; chemically inactive
   "inert matter"; "an indifferent chemical in a reaction"
   inert  indifferent  neutral 
   
5. possessing no distinctive quality or characteristics
   neutral 
   
6. lacking distinguishing quality or characteristics
   "a neutral personality that made no impression whatever"
   neutral 
   
7. not supporting or favoring either side in a war, dispute, or contest
   neutral 
   

1. one who does not side with any party in a war or dispute
   neutral