The Collaborative International Dictionary of English v.0.48:

Rub \Rub\, v. t. [imp. & p. p. Rubbed; p. pr. & vb. n.
   Rubbing.] [Probably of Celtic origin; cf. W. rhwbiaw, gael.
   rub.]
   1. To subject (a body) to the action of something moving over
      its surface with pressure and friction, especially to the
      action of something moving back and forth; as, to rub the
      flesh with the hand; to rub wood with sandpaper.
      [1913 Webster]

            It shall be expedient, after that body is cleaned,
            to rub the body with a coarse linen cloth. --Sir T.
                                                  Elyot.
      [1913 Webster]

   2. To move over the surface of (a body) with pressure and
      friction; to graze; to chafe; as, the boat rubs the
      ground.
      [1913 Webster]

   3. To cause (a body) to move with pressure and friction along
      a surface; as, to rub the hand over the body.
      [1913 Webster]

            Two bones rubbed hard against one another.
                                                  --Arbuthnot.
      [1913 Webster]

   4. To spread a substance thinly over; to smear.
      [1913 Webster]

            The smoothed plank, . . .
            New rubbed with balm.                 --Milton.
      [1913 Webster]

   5. To scour; to burnish; to polish; to brighten; to cleanse;
      -- often with up or over; as, to rub up silver.
      [1913 Webster]

            The whole business of our redemption is to rub over
            the defaced copy of the creation.     --South.
      [1913 Webster]

   6. To hinder; to cross; to thwart. [R.]
      [1913 Webster]

            'T is the duke's pleasure,
            Whose disposition, all the world well knows,
            Will not be rubbed nor stopped.       --Shak.
      [1913 Webster]

   To rub down.
      (a) To clean by rubbing; to comb or curry; as, to down a
          horse.
      (b) To reduce or remove by rubbing; as, to rub down the
          rough points.

   To rub off, to clean anything by rubbing; to separate by
      friction; as, to rub off rust.

   To rub out, to remove or separate by friction; to erase; to
      obliterate; as, to rub out a mark or letter; to rub out a
      stain.

   To rub up.
      (a) To burnish; to polish; to clean.
      (b) To excite; to awaken; to rouse to action; as, to rub
          up the memory.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rubbing \Rub"bing\,
   a. & n. from Rub, v.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rubbing
    n 1: the resistance encountered when one body is moved in
         contact with another [syn: friction, rubbing]
    2: representation consisting of a copy (as of an engraving) made
       by laying paper over something and rubbing it with charcoal
    3: effort expended in moving one object over another with
       pressure [syn: friction, detrition, rubbing]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "rubbing":
   apograph, brushing, carbon, carbon copy, caressing, companion,
   confrication, contacting, contingent, copy, dead ringer, double,
   duplicate, duplication, effigy, exact likeness, feeling, fellow,
   fiche, fingering, frication, fricative, friction, frictional,
   frottage, glancing, grazing, handling, hectography, icon, idol,
   image, impingent, impinging, in contact, likeness, living image,
   living picture, manifold, manipulation, match, mate, meeting,
   microcopy, microfiche, microform, mimeography, miniature,
   mirroring, model, nudging, osculatory, palpation, perfrication,
   petting, photograph, picture, portrait, pressure, recording,
   reduplication, reflection, reproduction, reprography, resemblance,
   rub, semblance, shadow, similitude, simulacrum, spit and image,
   spitting image, stroking, tangent, tangential, tenor, touching,
   trace, tracing, transcript, transcription, transfer, twin,
   very image, very picture, xerography