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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The Collaborative International Dictionary of English v.0.48:

Sparing \Spar"ing\, a.
   Spare; saving; frugal; merciful. --Bacon.
   [1913 Webster] -- Spar"ing*ly, adv. -- Spar"ing*ness, n.
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WordNet (r) 3.0 (2006):

sparing
    adj 1: avoiding waste; "an economical meal"; "an economical
           shopper"; "a frugal farmer"; "a frugal lunch"; "a sparing
           father and a spending son"; "sparing in their use of heat
           and light"; "stinting in bestowing gifts"; "thrifty
           because they remember the great Depression"; "`scotch' is
           used only informally" [syn: economical, frugal,
           scotch, sparing, stinting]

Moby Thesaurus II by Grady Ward, 1.0:

130 Moby Thesaurus words for "sparing":
   Lenten, Scotch, Spartan, absolution, abstemious, amnesty, ascetic,
   austere, benevolent, canny, careful, chary, cheap, cheeseparing,
   close, conciliatory, conserving, cooling, cooling down,
   cooling off, curtailment, cutback, dwarfed, dwarfish, economic,
   economical, economization, economizing, exculpation, excuse,
   exemption, exiguous, exoneration, forbearing, forehanded,
   forgiving, frugal, frugal to excess, generous, grace, immunity,
   impoverished, indemnity, jejune, kind, labor-saving, lean, limited,
   long-suffering, longanimous, low growth rate, magnanimous, meager,
   mean, measured, mingy, miserly, moderate, money-saving, narrow,
   niggardly, overfrugal, paltry, pardon, parsimonious, patient,
   penny-pinching, penny-wise, penny-wise and pound-foolish,
   penurious, placable, poor, provident, prudent, prudential, puny,
   redemption, reduction of expenses, reduction of spending,
   remission, remission of sin, reprieve, restrained, retrenchment,
   saving, scamping, scant, scanty, scraping, scrawny, scrimp,
   scrimping, scrimpy, shrift, skimp, skimping, skimpy, slender,
   slight, slim, slowdown, small, sober, spare, sparse, starvation,
   stingy, stinted, stinting, straitened, stunted, subsistence,
   temperate, thin, thrifty, tight, tight-fisted, tightfisted,
   time-saving, tolerant, too frugal, ungiving, unnourishing,
   unnutritious, unresentful, unrevengeful, unwasteful, wary, watered,
   watery