Insensible

Destitute of the power of feeling or perceiving; wanting bodily sensibility.

Not susceptible of emotion or passion; void of feeling; apathetic; unconcerned; indifferent; as, insensible to danger, fear, love, etc.; -- often used with of or to.

Incapable of being perceived by the senses; imperceptible. Hence: Progressing by imperceptible degrees; slow; gradual; as, insensible motion.

Not sensible or reasonable; meaningless.