Spunky

Adjective

 * 1) Spirited or plucky.
 * 2)  Pertaining to or like spunk (semen).
 * 3)  Stained with semen.

Thesaurus
beany, bold, bulldoggish, combustible, courageous, dauntless, doughty, explosive, fearless, fiery, game, gamy, gritty, gutsy, gutty, hasty, high-spirited, hot, hot-tempered, hotheaded, mettlesome, nervy, passionate, peppery, pertinacious, plucky, quick, quick-tempered, red-blooded, resolute, short-tempered, spirited, spiritful, tenacious, tough, unfearing, volcanic

Etymology
From.