The Collaborative International Dictionary of English v.0.48:

Bane \Bane\ (b[=a]n), n. [OE. bane destruction, AS. bana
   murderer; akin to Icel. bani death, murderer, OHG. bana
   murder, bano murderer, Goth. banja stroke, wound, Gr. foney`s
   murderer, fo`nos murder, OIr. bath death, benim I strike.
   [root]31.]
   1. That which destroys life, esp. poison of a deadly quality.
      [Obs. except in combination, as in ratsbane, henbane,
      etc.]
      [1913 Webster]

   2. Destruction; death. [Obs.]
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            The cup of deception spiced and tempered to their
            bane.                                 --Milton.
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   3. Any cause of ruin, or lasting injury; harm; woe.
      [1913 Webster]

            Money, thou bane of bliss, and source of woe.
                                                  --Herbert.
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   4. A disease in sheep, commonly termed the rot.
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   Syn: Poison; ruin; destruction; injury; pest.
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The Collaborative International Dictionary of English v.0.48:

Bane \Bane\, v. t.
   To be the bane of; to ruin. [Obs.] --Fuller.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bane
    n 1: something causing misery or death; "the bane of my life"
         [syn: bane, curse, scourge, nemesis]

Moby Thesaurus II by Grady Ward, 1.0:

121 Moby Thesaurus words for "bane":
   abomination, annihilation, atrocity, bad, befoulment,
   biological death, blight, blood, bloodletting, bloodshed, braining,
   cessation of life, clinical death, contagion, corruption,
   crossing the bar, crying evil, curtains, damage, dealing death,
   death, death knell, deathblow, debt of nature, decease, defilement,
   demise, departure, despoliation, destroyer, destruction,
   destruction of life, detriment, dispatch, dissolution, doom, dying,
   ebb of life, end, end of life, ending, eternal rest, euthanasia,
   evil, execution, exit, expiration, extermination, extinction,
   extinguishment, fate, final summons, finger of death,
   flow of blood, going, going off, gore, grave, grievance,
   hand of death, harm, havoc, hurt, ill, immolation, infection,
   injury, jaws of death, kill, killing, knell, lapidation, last debt,
   last muster, last rest, last roundup, last sleep, leaving life,
   loss of life, making an end, martyrdom, martyrization,
   mercy killing, mischief, outrage, parting, passing, passing away,
   passing over, perishing, poison, poisoning, pollution, quietus,
   release, rest, reward, ritual killing, ritual murder, ruin,
   ruination, sacrifice, sentence of death, shades of death,
   shadow of death, shooting, slaughter, slaying, sleep,
   somatic death, stoning, summons of death, taking of life,
   the worst, toxin, undoing, venom, vexation, virus, woe, wrong



Bouvier's Law Dictionary, Revised 6th Ed (1856):

BANE. This word was formerly used to signify a malefactor. Bract. 1. 2, t.
8, c. 1.