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

impossible \impos"sible\, a. f., fr. l. impossibilis; pref.
   im- not + possibilis possible. see possible.
   not possible; incapable of being done, of existing, etc.;
   unattainable in the nature of things, or by means at command;
   insuperably difficult under the circumstances; absurd or
   impracticable; not feasible.
   1913 webster

         with men this is impossible; but with god all things
         are possible.                            --matt. xix.
                                                  26.
   1913 webster

         without faith it is impossible to please him. --heb.
                                                  xi. 6.
   1913 webster

   impossible quantity math., an imaginary quantity. see
      imaginary.

   syn: see impracticable.
        1913 webster
see also:
possible impossible quantity imaginary impracticable 

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

impossible \impos"sible\, n.
   an impossibility; as, he tried to do the impossible. obs.
   1913 webster

         "madam," quoth he, "this were an impossible"
                                                  --chaucer.
   1913 webster

[3] : WordNet (r) 2.0

impossible
     adj 1: not capable of occurring or being accomplished or dealt
            with; "an impossible dream"; "an impossible situation"
            ant: possible
     2: totally unlikely syn: inconceivable, out of the question,
         unimaginable
     3: used of persons or their behavior; "impossible behavior";
        "insufferable insolence" syn: insufferable, unacceptable,
         unsufferable
     n : something that cannot be done; "his assignment verged on the
         impossible"
see also:
possible inconceivable out of the question unimaginable insufferable unacceptable 
unsufferable 

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

107 moby thesaurus words for "impossible":
   i refuse, i will not, absurd, algorismic, algorithmic, aliquot,
   antic, barred, by no means, cardinal, closed-out,
   contrary to reason, count me out, crazy, cureless, decimal,
   differential, digital, even, exceptionable, excluded, exponential,
   fanciful, fantastic, farcical, figural, figurate, figurative,
   finite, fractional, hopeless, illogical, imaginary, immedicable,
   impair, impracticable, impractical, inadmissible, include me out,
   incomprehensible, inconceivable, incredible, incurable,
   indefensible, infeasible, infinite, integral, intolerable,
   irrational, irremediable, irreparable, logarithmic,
   logically impossible, logometric, ludicrous, negative, no, no go,
   not likely, not possible, nothing doing, numeral, numerary,
   numerative, numeric, objectionable, odd, ordinal, outlandish,
   outrageous, oxymoronic, pair, paradoxical, positive, possible,
   preposterous, prime, prohibited, radical, rational, real,
   reciprocal, ridiculous, ruled-out, self-contradictory, submultiple,
   surd, transcendental, unacceptable, unaccountable, unachievable,
   unattainable, unbelievable, uncorrectable, undesirable, unexpected,
   unfeasible, unimaginable, unobtainable, unrealizable, unreasonable,
   unsolvable, unsuitable, untenable, unthinkable, unworkable,
   weird

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