Stubborn.

Dürer, The Anzogen-Rennen, 1517

If any one should feel himself offended by our remarks, let him attack us in return —we shall not wince from the combat.  If his passes be successful, we will be the first to cry out, "A hit!  A hit!" and we doubt not we shall frequently lay ourselves open to the weapons of our assailants. 

But let them have a care how they run a tilting with us; they have to deal with stubborn foes, who can bear a world of pummelling; we will be relentless in our vengeance, and will fight "till from our bones the flesh be hack't."

Washington Irving from Salmagundi, or The Whim-Whams and Opinions of Launcelot Langstaff, Esq.