[1] : The Collaborative International Dictionary of English v.0.48

impalpable \impal"pable\, a. 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.
      1913 webster

   2. not material; intangible; incorporeal. "impalpable, void,
      and bodiless." --holland.
      1913 webster

   3. not apprehensible, or readily apprehensible, by the mind;
      unreal; as, impalpable distinctions.
      1913 webster

[2] : WordNet (r) 2.0

impalpable
     adj 1: incapable of being perceived by the senses especially the
            sense of touch; "the intangible constituent of
            energy"- james jeans syn: intangible ant: tangible
     2: imperceptible to the senses or the mind; "an impalpable
        cloud"; "impalpable shadows"; "impalpable distinctions";
        "as impalpable as a dream" ant: palpable
     3: not perceptible to the touch; "an impalpable pulse"
see also:
intangible tangible palpable 

[3] : Moby Thesaurus II by Grady Ward, 1.0

99 moby thesaurus words for "impalpable":
   airy, asomatous, astral, atomic, bodiless, branny, chalklike,
   chalky, comminute, comminuted, corpuscular, crushed, decarnate,
   decarnated, detrital, detrited, discarnate, disembodied,
   disintegrated, dusty, efflorescent, embryonic, ethereal,
   evanescent, extramundane, farinaceous, fine, flaky, floury,
   furfuraceous, germinal, ghostly, gone to dust, granular, grated,
   ground, immaterial, imperceptible, imponderable, inappreciable,
   incorporate, incorporeal, indiscernible, infinitesimal, insensible,
   insubstantial, intangible, invisible, levigated, mealy,
   microcosmic, microscopic, milled, molecular, nonmaterial,
   nonphysical, nonsubstantial, occult, otherworldly, pestled,
   phantom, powdered, powdery, psychic, pulverant, pulverized,
   pulverulent, reduced to powder, scaly, scobicular, scobiform,
   scurfy, shadowy, sharded, shredded, spiritual, subatomic,
   supernatural, tenuous, thin, transmundane, triturated,
   ultramicroscopic, unapparent, unappreciable, unconcrete, unearthly,
   unembodied, unextended, unfleshly, unobservable, unperceivable,
   unphysical, unseeable, unsolid, unsubstanced, unsubstantial,
   unworldly, weightless

Impalpable >> I Words
Impalpable, definition of term: Impalpable
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