The Collaborative International Dictionary of English v.0.48:

Working \Work"ing\,
   a & n. from Work.
   [1913 Webster]

         The word must cousin be to the working.  --Chaucer.
   [1913 Webster]

   Working beam. See Beam, n. 10.

   Working class, the class of people who are engaged in
      manual labor, or are dependent upon it for support;
      laborers; operatives; -- chiefly used in the plural.

   Working day. See under Day, n.

   Working drawing, a drawing, as of the whole or part of a
      structure, machine, etc., made to a scale, and intended to
      be followed by the workmen. Working drawings are either
      general or detail drawings.

   Working house, a house where work is performed; a
      workhouse.

   Working point (Mach.), that part of a machine at which the
      effect required; the point where the useful work is done.
      [1913 Webster]

WordNet (r) 3.0 (2006):

working class
    n 1: a social class comprising those who do manual labor or work
         for wages; "there is a shortage of skilled labor in this
         field" [syn: labor, labour, working class,
         proletariat]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "working class":
   bourgeois, bourgeoisie, common people, common run, common sort,
   commonage, commonality, commonalty, commoners, commons, laborers,
   linendrapers, lower classes, lower middle class, lower orders,
   lumpen proletariat, middle class, middle orders, middle-class,
   ordinary people, peasantry, plain folks, plain people, proletarian,
   proletariat, rank and file, shopkeepers, small tradesmen,
   the lower cut, the other half, the third estate, toilers,
   toiling class, upper middle class, vulgus, working people