The Collaborative International Dictionary of English v.0.48:

moderating \moderating\ adj.
   lessening in intensity or strength. Opposite of
   intensifying. [Narrower terms: tempering; weakening]
   [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Temper \Tem"per\, v. t. [imp. & p. p. Tempered; p. pr. & vb.
   n. Tempering.] [AS. temprian or OF. temper, F. temp['e]rer,
   and (in sense 3) temper, L. temperare, akin to tempus time.
   Cf. Temporal, Distemper, Tamper.]
   1. To mingle in due proportion; to prepare by combining; to
      modify, as by adding some new element; to qualify, as by
      an ingredient; hence, to soften; to mollify; to assuage;
      to soothe; to calm.
      [1913 Webster]

            Puritan austerity was so tempered by Dutch
            indifference, that mercy itself could not have
            dictated a milder system.             --Bancroft.
      [1913 Webster]

            Woman! lovely woman! nature made thee
            To temper man: we had been brutes without you.
                                                  --Otway.
      [1913 Webster]

            But thy fire
            Shall be more tempered, and thy hope far higher.
                                                  --Byron.
      [1913 Webster]

            She [the Goddess of Justice] threw darkness and
            clouds about her, that tempered the light into a
            thousand beautiful shades and colors. --Addison.
      [1913 Webster]

   2. To fit together; to adjust; to accomodate.
      [1913 Webster]

            Thy sustenance . . . serving to the appetite of the
            eater, tempered itself to every man's liking.
                                                  --Wisdom xvi.
                                                  21.
      [1913 Webster]

   3. (Metal.) To bring to a proper degree of hardness; as, to
      temper iron or steel.
      [1913 Webster]

            The tempered metals clash, and yield a silver sound.
                                                  --Dryden.
      [1913 Webster]

   4. To govern; to manage. [A Latinism & Obs.]
      [1913 Webster]

            With which the damned ghosts he governeth,
            And furies rules, and Tartare tempereth. --Spenser.
      [1913 Webster]

   5. To moisten to a proper consistency and stir thoroughly, as
      clay for making brick, loam for molding, etc.
      [1913 Webster]

   6. (Mus.) To adjust, as the mathematical scale to the actual
      scale, or to that in actual use.
      [1913 Webster]

   Syn: To soften; mollify; assuage; soothe; calm.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Tempering \Tem"per*ing\, n. (Metal.)
   The process of giving the requisite degree of hardness or
   softness to a substance, as iron and steel; especially, the
   process of giving to steel the degree of hardness required
   for various purposes, consisting usually in first plunging
   the article, when heated to redness, in cold water or other
   liquid, to give an excess of hardness, and then reheating it
   gradually until the hardness is reduced or drawn down to the
   degree required, as indicated by the color produced on a
   polished portion, or by the burning of oil.
   [1913 Webster]

   Tempering color, the shade of color that indicates the
      degree of temper in tempering steel, as pale straw yellow
      for lancets, razors, and tools for metal; dark straw
      yellow for penknives, screw taps, etc.; brown yellow for
      axes, chisels, and plane irons; yellow tinged with purple
      for table knives and shears; purple for swords and watch
      springs; blue for springs and saws; and very pale blue
      tinged with green, too soft for steel instruments.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tempering
    adj 1: moderating by making more temperate
    n 1: hardening something by heat treatment [syn: annealing,
         tempering]

Moby Thesaurus II by Grady Ward, 1.0:

153 Moby Thesaurus words for "tempering":
   abatement, abating, ability, aging, allaying, allayment,
   alleviating, alleviation, arteriosclerosis, assuagement, assuaging,
   atherosclerosis, background, blaseness, blunting, calcification,
   callusing, calming, capability, case hardening, chastening,
   chisel temper, competence, competency, concretion, condition,
   cornification, crystallization, cushioning, dampening, damping,
   dash, deadening, demulsion, development, die temper, diminishing,
   diminution, dulcification, dulling, easing, experience,
   falling-off, firming, fitness, fittedness, fortification,
   fossilization, granulation, hardening, hardness scale,
   heat treating, hint, hornification, hushing, indenter, induration,
   infusion, inkling, intimation, invigoration, lapidification,
   leniency, lessening, letdown, letup, lightening, lithification,
   loosening, lulling, mastery, maturation, maturescence, maturity,
   mellowing, mitigating, mitigation, modulation, mollification,
   ossification, pacification, palliation, past experience,
   petrifaction, petrification, practical knowledge, practice,
   precipitation hardening, preparedness, proficiency, qualification,
   quietening, quieting, razor temper, readiness, reducing, reduction,
   refreshment, reinforcement, reinvigoration, relaxation, relaxing,
   remission, restrengthening, revivification, ripeness, ripening,
   sagacity, sauce, saw file temper, sclerosis, seasoning, senescence,
   set temper, setting, shade, slackening, smack, softening,
   solidification, soothing, sophistication, soupcon, spice,
   spindle temper, sprinkling, steeling, stiffening, strengthening,
   subduement, subduing, suggestion, suitability, suitableness,
   suitedness, suspicion, taint, temper, thought, tinct, tincture,
   tinge, tint, tool temper, touch, toughening, trace,
   tranquilization, trim, vestige, vitrifaction, vitrification,
   worldly wisdom