Adjective: unperceivable ,ún-pu(r)'see-vu-bul
- Impossible or difficult to perceive by the mind or senses
"colour is unperceivable to the touch";
- imperceptible
See also: impalpable, inaudible, incognisable [Brit], incognizable, incognoscible, indiscernible, insensible, invisible, subliminal, undetectable, unhearable, unobservable, unseeable