unperceivable
1. [ adjective ] impossible or difficult to perceive by the mind or senses
Synonyms: imperceptible
Examples:

"an imperceptible drop in temperature" "an imperceptible nod" "color is unperceivable to the touch"

Related terms: perceptible indiscernible incognizable impalpable subliminal unobservable invisible inaudible impalpable
Similar spelling:   unperceived
  unperceptive
  unperceiving
  unappreciated
  unpersuadable
  unappreciative
  unperceptiveness
  unapproachable
  unappreciatively
  unforgivable
  unperturbed
  unperformed