The Collaborative International Dictionary of English v.0.48:

Shear \Shear\, v. i.
   1. To deviate. See Sheer.
      [1913 Webster]

   2. (Engin.) To become more or less completely divided, as a
      body under the action of forces, by the sliding of two
      contiguous parts relatively to each other in a direction
      parallel to their plane of contact.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shear \Shear\, n. [AS. sceara. See Shear, v. t.]
   1. A pair of shears; -- now always used in the plural, but
      formerly also in the singular. See Shears.
      [1913 Webster]

            On his head came razor none, nor shear. --Chaucer.
      [1913 Webster]

            Short of the wool, and naked from the shear.
                                                  --Dryden.
      [1913 Webster]

   2. A shearing; -- used in designating the age of sheep.
      [1913 Webster]

            After the second shearing, he is a two-shear ram; .
            . . at the expiration of another year, he is a
            three-shear ram; the name always taking its date
            from the time of shearing.            --Youatt.
      [1913 Webster]

   3. (Engin.) An action, resulting from applied forces, which
      tends to cause two contiguous parts of a body to slide
      relatively to each other in a direction parallel to their
      plane of contact; -- also called shearing stress, and
      tangential stress.
      [1913 Webster]

   4. (Mech.) A strain, or change of shape, of an elastic body,
      consisting of an extension in one direction, an equal
      compression in a perpendicular direction, with an
      unchanged magnitude in the third direction.
      [1913 Webster]

   Shear blade, one of the blades of shears or a shearing
      machine.

   Shear hulk. See under Hulk.

   Shear steel, a steel suitable for shears, scythes, and
      other cutting instruments, prepared from fagots of
      blistered steel by repeated heating, rolling, and tilting,
      to increase its malleability and fineness of texture.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shear \Shear\ (sh[=e]r), v. t. [imp. Shearedor Shore;p. p.
   Sheared or Shorn; p. pr. & vb. n. Shearing.] [OE.
   sheren, scheren, to shear, cut, shave, AS. sceran, scieran,
   scyran; akin to D. & G. scheren, Icel. skera, Dan. ski?re,
   Gr. ???. Cf. Jeer, Score, Shard, Share, Sheer to
   turn aside.]
   1. To cut, clip, or sever anything from with shears or a like
      instrument; as, to shear sheep; to shear cloth.
      [1913 Webster]

   Note: It is especially applied to the cutting of wool from
         sheep or their skins, and the nap from cloth.
         [1913 Webster]

   2. To separate or sever with shears or a similar instrument;
      to cut off; to clip (something) from a surface; as, to
      shear a fleece.
      [1913 Webster]

            Before the golden tresses . . . were shorn away.
                                                  --Shak.
      [1913 Webster]

   3. To reap, as grain. [Scot.] --Jamieson.
      [1913 Webster]

   4. Fig.: To deprive of property; to fleece.
      [1913 Webster]

   5. (Mech.) To produce a change of shape in by a shear. See
      Shear, n., 4.
      [1913 Webster]

WordNet (r) 3.0 (2006):

shear
    n 1: (physics) a deformation of an object in which parallel
         planes remain parallel but are shifted in a direction
         parallel to themselves; "the shear changed the
         quadrilateral into a parallelogram"
    2: a large edge tool that cuts sheet metal by passing a blade
       through it
    v 1: cut with shears; "shear hedges"
    2: shear the wool from; "shear sheep" [syn: fleece, shear]
    3: cut or cut through with shears; "shear the wool off the lamb"
    4: become deformed by forces tending to produce a shearing
       strain

Moby Thesaurus II by Grady Ward, 1.0:

111 Moby Thesaurus words for "shear":
   abbreviate, abridge, abscind, abstract, amputate, annihilate, ban,
   bar, barb, barber, bare, bleed, bleed white, bob, boil down,
   capsulize, clip, compress, condense, contract, crop, cull, curtail,
   cut, cut away, cut back, cut down, cut off, cut off short, cut out,
   cut short, denudate, denude, deplume, despoil, displume, divest,
   dock, drain, dry, elide, eliminate, enucleate, epitomize,
   eradicate, except, excise, exclude, exhaust, expose, extinguish,
   extirpate, flay, fleece, foreshorten, impoverish, isolate,
   knock off, lay bare, lay open, lop, manicure, milk, mow, mutilate,
   nip, pare, peel, pick clean, pick out, pluck, poll, pollard, prune,
   reap, recap, recapitulate, reduce, remove, retrench, root out,
   rule out, set apart, set aside, shave, shorten, skin, skive, snip,
   snub, stamp out, strike off, strip, strip bare, strip off, stunt,
   suck dry, sum up, summarize, synopsize, take in, take off,
   take out, telescope, trim, truncate, uncloak, uncover, unsheathe,
   unveil, wipe out