IMPALPABLE
impalpable
(adjective) imperceptible to the senses or the mind; “an impalpable cloud”; “impalpable shadows”; “impalpable distinctions”; “as impalpable as a dream”
impalpable
(adjective) not perceptible to the touch; “an impalpable pulse”
intangible, impalpable
(adjective) incapable of being perceived by the senses especially the sense of touch; “the intangible constituent of energy”- James Jeans
Source: WordNet® 3.1
Etymology
Adjective
impalpable (comparative more impalpable, superlative most impalpable)
Not able to be perceived by the senses (especially by touch); intangible or insubstantial.
Not easily grasped or understood.
Source: Wiktionary
Im*pal"pa*ble, a. Etym: [Pref. im- not + palpable: cf. F.
impalpable.]
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 Edition