tweedledum and tweedledee

/T W IY1 D AH0 L D AH0 M AH0 N D T W IY0 D L AH0 D IY0/
noun
  1. 1

    (derogatory) Two persons or organizations deemed indistinguishable in some way.

  2. 2

    (derogatory) A pair of people who spend a lot of time together, and look and act similarly.