Athleticism is the quality of having the kind of strength and energy that makes a great athlete. It takes athleticism to run marathons, play pro football, or sprint down a cobblestone street in high heels without falling.
Athleticism might get you a basketball scholarship to college or help you win most of the tennis matches you play. When you're particularly good at a sport, people will praise your athleticism. Although it’s usually used with sports, athleticism can describe any quality of strength and energy. It takes musical athleticism to play Ravel’s Gaspard de la nuit on piano. The word is rooted in the Greek athlētēs, "prizefighter or contestant in the games."