Undistinguishable

The distinction between hardcore soccer fans and criminals is becoming more and more undistinguishable.

He wore an old-fashioned great-coat, much faded, within which his meagre person was so completely enveloped that the rest of his attire was undistinguishable.

Here I obtained the rare and beautiful swallow-tail butterflies, Papilio aenomaus and P. liris; the males of which are quite unlike each other, and belong in fact to distinct sections of the genus, while the females are so much alike that they are undistinguishable on the wing, and to an uneducated eye equally so in the cabinet.