effort (n.)

late 15c., "laborious attempt, strenuous exertion," from Middle French effort, from Old French esforz "force, impetuosity, strength, power," verbal noun from esforcier "force out, exert oneself," from Vulgar Latin *exfortiare "to show strength" (source of Italian sforza), from Latin ex "out" (see ex-) + Latin fortis "strong" (see fort).

Effort is only effort when it begins to hurt. [Ortega y Gasset, 1949]

Related: Efforts "voluntary exertion," also "result of exertion."