undistinguishable

from WordNet (r) 3.0 (2006)
undistinguishable
    adj 1: 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: {indistinguishable}, {undistinguishable}] [ant:
           {distinguishable}]