The Collaborative International Dictionary of English v.0.48:

Alloy \Al*loy"\, n. [OE. alai, OF. alei, F. aloyer, to alloy,
   alier to ally. See Alloy, v. t.]
   1. Any combination or compound of metals fused together; a
      mixture of metals; for example, brass, which is an alloy
      of copper and zinc. But when mercury is one of the metals,
      the compound is called an amalgam.
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   2. The quality, or comparative purity, of gold or silver;
      fineness.
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   3. A baser metal mixed with a finer.
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            Fine silver is silver without the mixture of any
            baser metal. Alloy is baser metal mixed with it.
                                                  --Locke.
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   4. Admixture of anything which lessens the value or detracts
      from; as, no happiness is without alloy. "Pure English
      without Latin alloy." --F. Harrison.
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The Collaborative International Dictionary of English v.0.48:

Alloy \Al*loy"\, v. t. [imp. & p. p. Alloyed; p. pr. & vb. n.
   Alloying.] [F. aloyer, OF. alier, allier, later allayer,
   fr. L. aligare. See Alloy, n., Ally, v. t., and cf.
   Allay.]
   1. To reduce the purity of by mixing with a less valuable
      substance; as, to alloy gold with silver or copper, or
      silver with copper.
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   2. To mix, as metals, so as to form a compound.
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   3. To abate, impair, or debase by mixture; to allay; as, to
      alloy pleasure with misfortunes.
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The Collaborative International Dictionary of English v.0.48:

Alloy \Al*loy"\, v. t.
   To form a metallic compound.
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         Gold and iron alloy with ease.           --Ure.
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Moby Thesaurus II by Grady Ward, 1.0:

175 Moby Thesaurus words for "alloy":
   Carboloy, Duralumin, Duriron, German silver, Monel Metal,
   Muntz metal, Stellite, Swedish steel, admix, admixture, adulterate,
   aggregate, allay, alloy iron, alloy steel, alloyage, alnico, alter,
   amalgam, amalgamate, amalgamation, babbitt, bell metal, bemingle,
   blend, brass, bronze, bush metal, canker, carbon steel,
   case-hardened steel, cast iron, change, cheapen, chisel steel,
   chrome-nickel steel, cinder pig, coalesce, coarsen, coin nickel,
   coin silver, combination, combine, combo, commingle, commix,
   commixture, compose, composite, composition, compound, concoct,
   concoction, confection, confound, conglomerate, constantan,
   contaminate, corrupt, cupronickel, damask, debase, debauch,
   decarbonized iron, defile, deflower, degenerate, degrade, denature,
   dental gold, deprave, desecrate, despoil, devalue, die steel,
   diminish, distort, drill steel, elinvar, emulsify, ensemble, fuse,
   fuse metal, fusion, galvanized iron, gilding metal, graphite steel,
   green gold, grid metal, gun metal, hard lead, hash, high brass,
   high-speed steel, homogenize, hot-work steel, immingle, immix,
   immixture, impair, infect, integrate, interblend, interfusion,
   interlace, interlard, intermingle, intermix, intermixture,
   intertwine, interweave, invar, jumble, knead, leaded bronze, magma,
   manganese bronze, merge, mingle, mingle-mangle, misuse, mix,
   mix up, mixture, moderate, modify, naval brass, nickel bronze,
   nickel silver, paste, pervert, pewter, phosphor bronze, pig,
   pinchbeck, poison, pollute, prostitute, ravage, ravish, red brass,
   rose metal, scramble, shot metal, shuffle, silicon bronze,
   silicon steel, solder, spiegeleisen, stainless steel, steel,
   sterling silver, stir up, structural iron, syncretize, taint,
   temper, throw together, tombac, tool steel, toss together,
   tula metal, twist, type metal, ulcerate, violate, vitiate,
   vulgarize, warp, white gold, white metal, work, wrought iron,
   yellow brass, yellow metal