indistinguishable \in`distin"guishable\
   i^n`di^sti^ng"gwi^sh.ab'l, a.
   not distinguishable; not capable of being perceived, known,
   or discriminated as separate and distinct; hence, not capable
   of being perceived or known; as, in the distance the flagship
   was indisguishable; the two copies were indisguishable in
   form or color; the difference between them was
   indisguishable.
   1913 webster

indistinguishable
     adj 1: exactly alike; incapable of being perceived as different;
            "rows of identical houses"; "cars identical except for
            their license plates"; "they wore indistinguishable
            hats" syn: identical
     2: not capable of being distinguished or differentiated; "the
        two specimens are actually different from each other but
        the differences are almost indistinguishable"; "the twins
        were indistinguishable"; "a colorless person quite
        indistinguishable from the colorless mass of humanity"
        syn: undistinguishable ant: distinguishable
see also:
identical undistinguishable distinguishable 

68 moby thesaurus words for "indistinguishable":
   alike, all one, all the same, blear, bleared, bleary, blurred,
   blurry, confused, consubstantial, dark, dim, duplicate, equal,
   equivalent, exactly alike, faint, feeble, filmy, foggy, fuzzy,
   half-seen, half-visible, hazy, homoousian, identic, identical,
   ill-defined, imperceptible, inconspicuous, indefinite,
   indiscernible, indistinct, indistinctive, inseparable,
   interchangeable, just alike, like, low-profile, merely glimpsed,
   misty, obscure, one, out of focus, pale, same, selfsame,
   semivisible, shadowy, standard, stereotyped, tantamount, twin,
   uncertain, unclear, undefined, undifferent, undifferentiated,
   undiscriminated, undistinguishable, undistinguished, uniform,
   unplain, unrecognizable, vague, weak, without difference,
   without distinction