To catch a tartar

from The Collaborative International Dictionary of English v.0.48

Tartar \Tar"tar\, n.
   1. [Per. T[=a]t[=a]r, of Tartar origin.] A native or
      inhabitant of Tartary in Asia; a member of any one of
      numerous tribes, chiefly Moslem, of Turkish origin,
      inhabiting the Russian Europe; -- written also, more
      correctly but less usually, {Tatar}.
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   2. A person of a keen, irritable temper.
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   {To catch a tartar}, to lay hold of, or encounter, a person
      who proves too strong for the assailant. [Colloq.]
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