indistinguishable

Adjective

• 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
    

• exactly alike; incapable of being perceived as different
  • rows of identical houses
    
  • cars identical except for their license plates
    
  • they wore indistinguishable hats
    

Related words

• Synonyms: 
  undistinguishable , identical