tweedledum and tweedledee

twee·dle·dum and twee·dle·dee  (twdl-dm n twdl-d)

n.

Two people or two groups resembling each other so closely that they are practically indistinguishable.

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[After Tweedledum and Tweedledee, names of two proverbial rival fiddlers, of imitative origin.]

Thesaurus

Noun

1.

Tweedledum and Tweedledee - any two people who are hard to tell apart Tweedledee and Tweedledum pair, brace - a set of two similar things considered as a unit