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.
2. A person of a keen, irritable temper.
To catch a tartar, to lay hold of, or encounter, a person
who proves too strong for the assailant. [Colloq.]