1.  effort(n = noun.act) attempt, endeavor, endeavour, try - earnest and conscientious activity intended to do or accomplish something; "made an effort to cover all the reading material"; "wished him luck in his endeavor"; "she gave it a good try"
is a kind of activity
has particulars: batting, best, worst, bid, play, crack, fling, go, offer, pass, whirl, essay, foray, contribution, part, share, liberation, mug's game, power play, squeeze, squeeze play, seeking, shot, stab, shot, nisus, pains, strain, striving, battle, struggle, takeover attempt, run, test, trial, test, trial

2.  effort(n = noun.act) elbow grease, exertion, sweat, travail - use of physical or mental energy; hard work; "he got an A for effort"; "they managed only with great exertion"
is a kind of labor, labour, toil
has particulars: struggle, difficulty, trouble, least effort, least resistance, strain, straining, exercise, exercising, physical exercise, physical exertion, workout, pull, application, diligence, overkill, supererogation, overexertion, detrition, friction, rubbing

3.  effort(n = noun.act) exploit, feat - a notable achievement; "he performed a great feat"; "the book was her finest effort"
is a kind of accomplishment, achievement
has particulars: derring-do, hit, rally, rallying, stunt, tour de force

4.  effort(n = noun.act) campaign, cause, crusade, drive, movement - a series of actions advancing a principle or tending toward a particular end; "he supported populist campaigns"; "they worked in the cause of world peace"; "the team was ready for a drive toward the pennant"; "the movement to end slavery"; "contributed to the war effort"
is a kind of venture
has particulars: ad blitz, ad campaign, advertising campaign, anti-war movement, charm campaign, consumerism, campaigning, candidacy, candidature, electioneering, political campaign, fund-raising campaign, fund-raising drive, fund-raising effort, feminism, feminist movement, women's lib, women's liberation movement, gay lib, gay liberation movement, lost cause, reform, war, youth crusade, youth movement

1.  An exertion of strength or power, whether physical or mental, in performing an act or aiming at an object; more or less strenuous endeavor; struggle directed to the accomplishment of an object; as, an effort to scale a wall. [1913 Webster]
"We prize the stronger effort of his power." [1913 Webster]

2.  A force acting on a body in the direction of its motion. Rankine.

   To stimulate. Fuller. [1913 Webster]

effort, n.
1 strenuous physical or mental exertion.
2 a vigorous or determined attempt.
3 Mech. a force exerted.
4 colloq. the result of an attempt; something accomplished (not bad for a first effort).

Derivative:
effortful adj.

Etymology:
F f. OF esforcier ult. f. L fortis strong

N  exertion, effort, strain, tug, pull, stress, throw, stretch, struggle, spell, spurt, spirt, stroke of work, stitch of work, a strong pull a long pull and a pull all together, dead lift, heft, gymnastics, exercise, exercitation, wear and tear, ado, toil and trouble, uphill work, hard work, warm work, harvest time, labor, work, toil, travail, manual labor, sweat of one's brow, swink, drudgery, slavery, fagging, hammering, limae labor, industry, industriousness, operoseness, operosity, trouble, pains, duty, resolution, energy, laboring, laborious, operose, elaborate, strained, toilsome, troublesome, wearisome, uphill, herculean, gymnastic, palestric, hard-working, painstaking, strenuous, energetic, hard at work, on the stretch, laboriously, lustily, pugnis et calcibus, with might and main, with all one's might, with a strong hand, with a sledge hammer, with much ado, to the best of one's abilities, totis viribus, vi et armis, manibus pedibusque, tooth and nail, unguibus et rostro, hammer and tongs, heart and soul, through thick and thin, by the sweat of one's brow, suo Marte, aide-toi le ciel t'aidera, and still be doing, never done, buen principio la mitad es hecha, cosa ben fatta e' fatta due volie, it is better to wear out than to rust out, labor omnia vincit, labor, wide as the earth, has its summit in Heaven, le travail du corps delivre des peines de l'esprit, manu forti, ora et labora.

fund-raising effort, joint effort, least effort, waste of effort