WordWeb Online

1. Unaware of or indifferent to
   "insensible to the suffering around him";
   - unaffected
    
2. Barely able to be perceived
   "an almost insensible change";
   - indiscernible, undetectable
    
3. Unresponsive to stimulation
   "he lay insensible where he had fallen";
   - senseless, out of it
    
4. Incapable of physical sensation
   "insensible to pain"; "insensible earth"

See also: anaesthetic [Brit, Cdn], anesthetic [N. Amer], asleep, benumbed, imperceptible, incognisant [Brit], incognizant, insensitive, numb, unaware, unconscious, unperceivable

Antonym: sensitive

Encyclopedia: Insensible