Unperceivable
Part of speech: adjective
Definition: Not perceivable; imperceptible.
Insensible
Part of speech: adjective
Definition: Unable to be perceived by the senses.Incapable or deprived of physical sensation.Unable to be understood; unintelligible.Lacking sense or intelligence.Incapable of mental feeling; indifferent.Incapable of emotional feeling; callous; apathetic.