Impalpable
Pronunciation : Im*pal"pa*ble
Part of Speech : a.
Etymology : [Pref. im- not + palpable: cf. F. impalpable.]
Definition : 1. Not palpable; that cannot be felt; extremely fine, so that no grit can be perceived by touch. "Impalpable powder." Boyle.
2. Not material; intangible; incorporeal. "Impalpable, void, and bodiless." Holland.
3. Not apprehensible, or readily apprehensible, by the mind; unreal; as, impalpable distinctions.
Source : Webster's Unabridged Dictionary, 1913