The Collaborative International Dictionary of English v.0.48:

Shadow \Shad"ow\, v. t. [imp. & p. p. Shadowed; p. pr. & vb.
   n. Shadowing.] [OE. shadowen, AS. sceadwian. See adow,
   n.]
   1. To cut off light from; to put in shade; to shade; to throw
      a shadow upon; to overspead with obscurity.
      [1913 Webster]

            The warlike elf much wondered at this tree,
            So fair and great, that shadowed all the ground.
                                                  --Spenser.
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   2. To conceal; to hide; to screen. [R.]
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            Let every soldier hew him down a bough.
            And bear't before him; thereby shall we shadow
            The numbers of our host.              --Shak.
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   3. To protect; to shelter from danger; to shroud.
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            Shadowing their right under your wings of war.
                                                  --Shak.
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   4. To mark with gradations of light or color; to shade.
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   5. To represent faintly or imperfectly; to adumbrate; hence,
      to represent typically.
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            Augustus is shadowed in the person of [AE]neas.
                                                  --Dryden.
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   6. To cloud; to darken; to cast a gloom over.
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            The shadowed livery of the burnished sun. --Shak.
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            Why sad?
            I must not see the face O love thus shadowed.
                                                  --Beau. & Fl.
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   7. To attend as closely as a shadow; to follow and watch
      closely, especially in a secret or unobserved manner; as,
      a detective shadows a criminal.
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The Collaborative International Dictionary of English v.0.48:

Shadowing \Shad"ow*ing\, n.
   1. Shade, or gradation of light and color; shading.
      --Feltham.
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   2. A faint representation; an adumbration.
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            There are . . . in savage theology shadowings,
            quaint or majestic, of the conception of a Supreme
            Deity.                                --Tylor.
      [1913 Webster]

WordNet (r) 3.0 (2006):

shadowing
    n 1: the act of following someone secretly [syn: shadowing,
         tailing]

The Free On-line Dictionary of Computing (19 January 2023):

aliasing
shadowing

   1.  When several different identifiers refer to the
   same object.  The term is very general and is used in many
   contexts.

   See alias, aliasing bug, anti-aliasing.

   2.  (Or "shadowing") Where a hardware device
   responds at multiple addresses because it only decodes a
   subset of the address lines, so different values on the
   other lines are ignored.

   (1998-03-13)