need a Russian word

[kradical]

I'm writing a novel that includes a character who is given a mare who is difficult. This scene takes place in Russia, and what I need is the Russian word for "difficult," referring to a person.

Thanks!

Edited to add: I went with Trudnaya. Thanks everyone! Just FYI, this is for a Buffy the Vampire Slayer novel called The Deathless, which will be out next spring....