late 15c., "laborious attempt, strenuous exertion," from 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. [José Ortega y Gasset, writing of Goethe in Partisan Review, vol. xvi, part ii, 1949]

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

Old English læst, earlier læsest "smallest, lowest in power or position" (superlative of little (adj.)), from Proto-Germanic superlative *laisista-, from PIE root *leis- (2) "small" (see less). Qualifying phrase at least "not to say more than is certainly true" is Middle English æt læstan, from the notion of "at the lowest degree." As a noun, "smallest admissible quantity or degree," from early 12c.; as an adverb, Old English læst "in the least degree."

1752, "passive, making no effort," from effort + -less. Meaning "easy, requiring no effort" is from 1810. Related: Effortlessly; effortlessness.

1530s, "a putting forth of effort in some difficult or uncertain endeavor," from attempt (v.). The meaning "effort to accomplish something by violence" is from 1580s, especially as an assault on someone's life.

1550s, "a pull exerting the utmost effort (of a horse), from dead (adj.) + lift (n.). From 1560s in figurative sense of "a position in which one can do no more;" by 1882 as "an effort involving the whole strength."

"incomplete effort," 1798, from half + measure (n.).

"a gasping breath, a quick, short effort of breathing," c. 1500, from pant (v.).

"violent effort of a horse to throw off a rider," 1877, from buck (v.1).

1660s, "act of exerting," from exert + -ion. Meaning "vigorous action or effort" is from 1777.

"smallest, least; pertaining to a minimum," 1660s, from Latin minimus "smallest, least" (see minim) + -al (1).