fatigue

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Physical or mental weariness resulting from effort or activity.
• noun Something, such as tiring effort or activity, that causes tiredness or weariness.
• noun Physiology The decreased capacity or complete inability of an organism, organ, or part to function normally because of excessive stimulation or prolonged exertion.
• noun The weakening or failure of a material, such as metal or wood, resulting from prolonged stress.
• noun Manual or menial labor, such as barracks cleaning, assigned to soldiers.
• noun Clothing worn by military personnel for labor or for field duty.
• intransitive verb To tire out; exhaust.
• intransitive verb To create fatigue in (a metal or other material).
• intransitive verb To be or become tired. synonym: tire.

from The Century Dictionary.

• To weary with labor or any bodily or mental exertion; lessen or exhaust the strength of by severe or long-continued exertion, by trouble, by anything that harasses, etc.; tire.
• Synonyms Weary, Jade, etc. See tire, verb
• noun A feeling of weariness following bodily labor or mental exertion; a sense of loss or exhaustion of strength after exertion, trouble, etc.
• noun A cause or source of weariness; labor; toil: as, the fatigues of war.
• noun Specifically The labors of military men distinct from the use of arms; fatigue-duty: as, a party of men on fatigue.
• noun The weakening of a metal bar by the repeated application and removal of a load considerably less than the breaking-weight of the bar, as when car-axles break from the repeated blows and strains which they experience.
• noun Synonyms Fatigue, Weariness, Lassitude. Fatigue is more often physical, but also mental, and is generally the result of active and strenuous exertion: as, the fatigue of ten hours' work, or of close application to books. Weariness may be the same as fatigue; it is, more often than fatigue, the result of less obvious causes, as long sitting or standing in one position, importunity from others, delays, and the like. Fatigue and weariness are natural conditions, from which one easily recovers by rest. Lassitude is a relaxation with languor, the result of greater fatigue or weariness than one can well bear, and may be of the nature of ill health. The word may, however, be used in a lighter sense.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To weary with labor or any bodily or mental exertion; to harass with toil; to exhaust the strength or endurance of; to tire.
• noun Weariness from bodily labor or mental exertion; lassitude or exhaustion of strength.
• noun The cause of weariness; labor; toil.
• noun The weakening of a metal when subjected to repeated vibrations or strains.
• noun (Mil.) a summons, by bugle or drum, to perform fatigue duties.
• noun the working dress of soldiers.
• noun (Mil.) labor exacted from soldiers aside from the use of arms.
• noun a party of soldiers on fatigue duty.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A weariness caused by exertion; exhaustion.
• noun A menial task, especially in the military.
• noun A type of material failure due to cumulative effects of cyclic loading.
• verb transitive to tire or make weary by physical or mental exertion
• verb intransitive to lose so much strength or energy that one becomes tired, weary, feeble or exhausted

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun used of materials (especially metals) in a weakened state caused by long stress
• verb lose interest or become bored with something or somebody
• noun temporary loss of strength and energy resulting from hard physical or mental work
• noun (always used with a modifier) boredom resulting from overexposure to something
• verb exhaust or get tired through overuse or great strain or stress
• noun labor of a nonmilitary kind done by soldiers (cleaning or digging or draining or so on)