The Collaborative International Dictionary of English v.0.48:

Whet \Whet\, n.
   [1913 Webster]
   1. The act of whetting.
      [1913 Webster]

   2. That which whets or sharpens; esp., an appetizer. "Sips,
      drams, and whets." --Spectator.
      [1913 Webster]

   Whet slate (Min.), a variety of slate used for sharpening
      cutting instruments; novaculite; -- called also whetstone
      slate, and oilstone.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Whet \Whet\, v. t. [imp. & p. p. Whetted; p. pr. & vb. n.
   Whetting.] [AS. hwettan; akin to D. wetten, G. wetzen, OHG.
   wezzen, Icel. hvetja, Sw. v[aum]ttja, and AS. hw[ae]t
   vigorous, brave, OS. hwat, OHG. waz, was, sharp, Icel. hvatr,
   bold, active, Sw. hvass sharp, Dan. hvas, Goth. hwassaba
   sharply, and probably to Skr. cud to impel, urge on.]
   [1913 Webster]
   1. To rub or on with some substance, as a piece of stone, for
      the purpose of sharpening; to sharpen by attrition; as, to
      whet a knife.
      [1913 Webster]

            The mower whets his scythe.           --Milton.
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            Here roams the wolf, the eagle whets his beak.
                                                  --Byron.
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   2. To make sharp, keen, or eager; to excite; to stimulate;
      as, to whet the appetite or the courage.
      [1913 Webster]

            Since Cassius first did whet me against Caesar,
            I have not slept.                     --Shak.
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   To whet on, To whet forward, to urge on or forward; to
      instigate. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

whet
    v 1: make keen or more acute; "whet my appetite" [syn: whet,
         quicken]
    2: sharpen by rubbing, as on a whetstone

Moby Thesaurus II by Grady Ward, 1.0:

130 Moby Thesaurus words for "whet":
   accelerate, aculeate, acuminate, aggravate, agitate, animate,
   antepast, antipasto, aperitif, appetizer, arouse, awaken, bait,
   barb, beef up, bestir, blow the coals, blow up, bribe, canape,
   carrot, challenge, complicate, concentrate, condense, consolidate,
   cultivate, cuspidate, deepen, double, edge, encouragement, enhance,
   enliven, exacerbate, exaggerate, excite, exhilarate, fan,
   fan the flame, feed the fire, ferment, file, fillip, fire, foment,
   foretaste, galvanize, grind, heat, heat up, heighten, hone, hop up,
   hot up, impassion, incense, incentive, incite, incitement,
   inducement, inflame, infuse life into, instigate, intensify,
   interest, invigorate, invitation, jazz up, key up, kindle, lure,
   magnify, make complex, make sensitive, nettle, oilstone, payment,
   percentage, persuasive, pick up, pique, point, profit, provocation,
   provoke, put up to, quicken, rally, ramify, redouble, refine,
   reinforce, renew, reset, resuscitate, revive, reward, rouse,
   sensibilize, sensitize, set, set on, sharp, sharpen, sic on,
   smorgasbord, soup up, spiculate, spur, step up, stimulate,
   stimulation, stimulative, stimulus, stir, stir the embers, stir up,
   strap, strengthen, strop, sweetener, sweetening, taper, tickle,
   triple, wake, waken, whip up, work up