imponderable

• POS: Adjective, Noun
• HYPHEN: im=pon=der=a=ble

CIDE DICTIONARY

imponderable, a. [Pref. im- not + ponderable: cf. F. impondérable.].

 Not ponderable; without sensible or appreciable weight; incapable of being weighed.  [1913 Webster]

imponderable, n. 

 An imponderable substance or body; specifically, in the plural, a name formerly applied to heat, light, electricity, and magnetism, regarded as subtile fluids destitute of weight but in modern science little used.  [1913 Webster]

OXFORD DICTIONARY

imponderable, adj. & n.
--adj.
1 that cannot be estimated or assessed in any definite way.
2 very light.
3 Physics having no weight.
--n. (usu. in pl.) something difficult or impossible to assess.

Derivative

imponderability n. imponderably adv.

THESAURUS

imponderable

airy, asomatous, astral, atomic, bodiless, corpuscular, decarnate, decarnated, discarnate, disembodied, embryonic, ethereal, evanescent, extramundane, germinal, ghostly, granular, immaterial, impalpable, imperceptible, inappreciable, incomprehensible, inconceivable, incorporate, incorporeal, indiscernible, inestimable, infinitesimal, insensible, insubstantial, intangible, invisible, microcosmic, microscopic, molecular, nonmaterial, nonphysical, nonsubstantial, occult, otherworldly, phantom, psychic, shadowy, spiritual, subatomic, subtle, supernatural, tenuous, thin, transmundane, ultramicroscopic, unapparent, unappreciable, unconcrete, unearthly, unembodied, unextended, unfleshly, unmeasurable, unobservable, unperceivable, unphysical, unseeable, unsolid, unsubstanced, unsubstantial, unweighable, unworldly, weightless

ROGET THESAURUS

imponderable

Levity

N levity, lightness, imponderability, buoyancy, volatility, feather, dust, mote, down, thistle, down, flue, cobweb, gossamer, straw, cork, bubble, balloon, float, buoy, ether, air, leaven, ferment, barm, yeast, lighter-than-air balloon, helium balloon, hydrogen balloon, hot air balloon, convection, thermal draft, thermal, light, subtile, airy, imponderous, imponderable, astatic, weightless, ethereal, sublimated, gossamery, suberose, suberous, uncompressed, volatile, buoyant, floating, portable, light as a feather, light as a thistle, light as air, lighter than air, rise like a balloon, float like a balloon.