STAMINA

n. ruggedness, vigour, vigorousness, (intestinal) fortitude, robustness, indefatigability, staying power, endurance, energy, power, might, mettle, (inner) strength, staunchness, stalwartness, courage, indomitability, Colloq grit, guts, starch, US stick-to-it-iveness, sand, Taboo slang balls Even at the age of 70, she still had the stamina to run in the marathon