The Collaborative International Dictionary of English v.0.48:

Spare \Spare\, v. t. [imp. & p. p. Spared; p. pr. & vb. n.
   Sparing.] [AS. sparian, fr. spaer spare, sparing, saving;
   akin to D. & G. sparen, OHG. spar?n, Icel. & Sw. spara, Dan.
   spare See Spare, a.]
   1. To use frugally or stintingly, as that which is scarce or
      valuable; to retain or keep unused; to save. "No cost
      would he spare." --Chaucer.
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            [Thou] thy Father's dreadful thunder didst not
            spare.                                --Milton.
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            He that hath knowledge, spareth his words. --Prov.
                                                  xvii. 27.
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   2. To keep to one's self; to forbear to impart or give.
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            Be pleased your plitics to spare.     --Dryden.
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            Spare my sight the pain
            Of seeing what a world of tears it costs you.
                                                  --Dryden.
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   3. To preserve from danger or punishment; to forbear to
      punish, injure, or harm; to show mercy to.
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            Spare us, good Lord.                  --Book of
                                                  Common Prayer.
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            Dim sadness did not spare
            That time celestial visages.          --Milton.
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            Man alone can whom he conquers spare. --Waller.
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   4. To save or gain, as by frugality; to reserve, as from some
      occupation, use, or duty.
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            All the time he could spare from the necessary cares
            of his weighty charge, he ?estowed on . . . serving
            of God.                               --Knolles.
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   5. To deprive one's self of, as by being frugal; to do
      without; to dispense with; to give up; to part with.
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            Where angry Jove did never spare
            One breath of kind and temperate air. --Roscommon.
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            I could have better spared a better man. --Shak.
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   To spare one's self.
      (a) To act with reserve. [Obs.]
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                Her thought that a lady should her spare.
                                                  --Chaucer.
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      (b) To save one's self labor, punishment, or blame.
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Moby Thesaurus II by Grady Ward, 1.0:

49 Moby Thesaurus words for "spared":
   absolved, acquitted, blotted, canceled, chartered, condoned,
   conserved, disregarded, excepted, exculpated, excused, exempt,
   exempted, exonerated, favored, forgiven, forgotten, immune,
   indulged, intact, irresponsible, kept, let off, licensed,
   overlooked, pardoned, permitted, preserved, privileged, protected,
   redeemed, released, remitted, reprieved, saved, shriven,
   unaccountable, unanswerable, unavenged, uncondemned, undamaged,
   unliable, unresented, unrevenged, unspoiled, unsubject, untainted,
   well-conserved, wiped away