The Collaborative International Dictionary of English v.0.48:

Steel \Steel\ (st[=e]l), v. t. [imp. & p. p. Steeled
   (st[=e]ld); p. pr. & vb. n. Steeling.] [AS. st[=y]lan: cf.
   Icel. staela. See Steel, n.]
   1. To overlay, point, or edge with steel; as, to steel a
      razor; to steel an ax.
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   2. Fig.: To make hard or strong; hence, to make insensible or
      obdurate.
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            Lies well steeled with weighty arguments. --Shak.
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            O God of battles! steel my soldiers' hearts. --Shak.
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            Why will you fight against so sweet a passion,
            And steel your heart to such a world of charms?
                                                  --Addison.
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   3. Fig.: To cause to resemble steel, as in smoothness,
      polish, or other qualities.
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            These waters, steeled
            By breezeless air to smoothest polish. --Wordsworth.
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   4. (Elec.) To cover, as an electrotype plate, with a thin
      layer of iron by electrolysis. The iron thus deposited is
      very hard, like steel.
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Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "steeled":
   Philistine, backed, calcified, callous, calloused, case-hardened,
   crusted, crusty, crystallized, flinty, fossilized, granulated,
   hard, hardened, hardhearted, hornified, impervious, incrusted,
   indurate, indurated, insensitive, inured, lapidified, ossified,
   pachydermatous, petrified, proof against, reinforced, rigidified,
   sclerotic, set, solidified, steeled against, steely, stiffened,
   stony, strengthened, thick-skinned, toughened, vitrified