insensible

Short definition from Wiktionary

Adjective

1. 1
   Unable to be perceived by the senses.
2. 2
   Incapable or deprived of physical sensation.
3. 3
   Unable to be understood; unintelligible.
4. 4
   Not sensible or reasonable; meaningless.
5. 5
   Incapable of mental feeling; indifferent.
6. 6
   Incapable of emotional feeling; callous; apathetic.