mettlesome

Adjective

mettlesome (comparative more mettlesome, superlative most mettlesome)

1. Marked by mettle or bravery; courageous.
   • The instant Haley touched the saddle, the mettlesome creature bounded from the earth with a sudden spring, that threw his master sprawling, some feet off, on the soft, dry turf.1852, Harriet Beecher Stowe, chapter 6, in Uncle Tom's Cabin
   • Among them was the "West Country" driver, Swain, of Bude, over the Great Central, who reminded me irresistibly of a hunter putting a particularly mettlesome steed at the fences.1948 September and October, Cecil J. Allen, “British Locomotive Practice and Performance”, in Railway Magazine, page 334