The Collaborative International Dictionary of English v.0.48:

Fatigue \Fa*tigue"\, v. t. [imp. & p. p. Fatigued; p. pr. &
   vb. n. Fatiguing, n.] [Cf. F. fatiguer. See Fatigue, n.]
   To weary with labor or any bodily or mental exertion; to
   harass with toil; to exhaust the strength or endurance of; to
   tire.

   Syn: To jade; tire; weary; bore. See Jade.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fatigue \Fa*tigue"\, n. [F., fr. fatiguer to fatigue, L.
   fatigare; cf. L. affatim sufficiently.]
   1. Weariness from bodily labor or mental exertion; lassitude
      or exhaustion of strength.
      [1913 Webster]

   2. The cause of weariness; labor; toil; as, the fatigues of
      war. --Dryden.
      [1913 Webster]

   3. The weakening of a metal when subjected to repeated
      vibrations or strains.
      [1913 Webster]

   Fatigue call (Mil.), a summons, by bugle or drum, to
      perform fatigue duties.

   Fatigue dress, the working dress of soldiers.

   Fatigue duty (Mil.), labor exacted from soldiers aside from
      the use of arms. --Farrow.

   Fatigue party, a party of soldiers on fatigue duty.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fatigue
    n 1: temporary loss of strength and energy resulting from hard
         physical or mental work; "he was hospitalized for extreme
         fatigue"; "growing fatigue was apparent from the decline in
         the execution of their athletic skills"; "weariness
         overcame her after twelve hours and she fell asleep" [syn:
         fatigue, weariness, tiredness]
    2: used of materials (especially metals) in a weakened state
       caused by long stress; "metal fatigue"
    3: (always used with a modifier) boredom resulting from
       overexposure to something; "he was suffering from museum
       fatigue"; "after watching TV with her husband she had a bad
       case of football fatigue"; "the American public is
       experiencing scandal fatigue"; "political fatigue"
    4: labor of a nonmilitary kind done by soldiers (cleaning or
       digging or draining or so on); "the soldiers were put on
       fatigue to teach them a lesson"; "they were assigned to
       kitchen fatigues" [syn: fatigue duty, fatigue]
    v 1: lose interest or become bored with something or somebody;
         "I'm so tired of your mother and her complaints about my
         food" [syn: tire, pall, weary, fatigue, jade]
    2: exhaust or get tired through overuse or great strain or
       stress; "We wore ourselves out on this hike" [syn: tire,
       wear upon, tire out, wear, weary, jade, wear out,
       outwear, wear down, fag out, fag, fatigue] [ant:
       freshen, refresh, refreshen]

Moby Thesaurus II by Grady Ward, 1.0:

251 Moby Thesaurus words for "fatigue":
   abatement, abscess, acedia, adynamia, ague, anemia, ankylosis,
   annoy, anoxia, apathy, apnea, asphyxiation, asthma, ataxia, atony,
   atrophy, attenuation, attrition, backache,
   be infinitely repetitive, be tedious, beat, blah feeling, bleeding,
   blennorhea, bloodlessness, blow, blunting, boredom, bother,
   break down, burn out, cachexia, cachexy, chill, chills, colic,
   collapse, constipation, convulsion, coughing, cowardice, crack up,
   cyanosis, damping, deadening, debilitate, debilitation, debility,
   deplete, devitalization, diarrhea, dilution, dirty work, disable,
   dizziness, do in, do up, donkeywork, drag on, drain, droop, drop,
   dropsy, drowsiness, drudgery, dulling, dullness, dysentery,
   dyspepsia, dyspnea, edema, effemination, emaciation, employment,
   enervate, enervation, enfeeblement, ennui, etiolation,
   evisceration, exhaust, exhaustion, extenuation, fag, fag out,
   faint, fainting, faintness, feebleness, fever, fibrillation,
   flabbiness, flaccidity, flag, flux, frazzle, gasp, get tired,
   give out, glut, go on forever, grind, grow weary, growth,
   handiwork, handwork, harass, heaviness, hebetude, hemorrhage,
   high blood pressure, hydrops, hypertension, hypotension, icterus,
   impotence, inanimation, inanition, indifference, indigestion,
   industry, inflammation, insomnia, irk, itching, jade, jadedness,
   jaundice, knock out, knock up, labor, labored breathing,
   lackadaisicalness, languidness, languishment, languor,
   languorousness, lassitude, lenitude, lentor, lethargy, lick,
   lick of work, lifelessness, listlessness, low blood pressure,
   lumbago, manual labor, marasmus, mitigation, moil, nasal discharge,
   nausea, necrosis, oscitancy, overfatigue, overstrain, overtire,
   overweary, pain, pall, pant, paralysis, passivity, peter out,
   phlegm, play out, poop, poop out, prostrate, prostration, pruritus,
   puff, puff and blow, rash, rat race, reduction, relaxation, rheum,
   run down, run out, satedness, satiate, sclerosis, scut work,
   seizure, shock, sink, skin eruption, slackening, slavery,
   sleepiness, sloth, slothfulness, slowness, sluggishness, sneezing,
   softening, softness, somnolence, sore, spadework, spasm,
   strengthlessness, stroke, stroke of work, stupefaction, stupor,
   succumb, supineness, sweat, tabes, tachycardia, task, thinning,
   tire, tire out, tire to death, tiredness, tiresome work, toil,
   torpidity, torpidness, torpitude, torpor, travail, treadmill,
   tucker, tumor, upset stomach, use up, vertigo, vex, vomiting,
   wasting, weaken, weakening, weakliness, weakness, wear, wear down,
   wear on, wear out, weariness, weary, wheeze, wilt, wind, work,
   world-weariness