The Collaborative International Dictionary of English v.0.48:

Toiler \Toil"er\, n.
   One who toils, or labors painfully.
   [1913 Webster]

WordNet (r) 3.0 (2006):

toiler
    n 1: one who works strenuously

Moby Thesaurus II by Grady Ward, 1.0:

80 Moby Thesaurus words for "toiler":
   blue-collar worker, bourgeoisie, breadwinner, casual,
   casual laborer, common laborer, common people, common run,
   common sort, commonage, commonality, commonalty, commoners,
   commons, day laborer, dray horse, drudge, employee, factory worker,
   flunky, free lance, free-lancer, full-time worker, galley slave,
   hand, industrial worker, jobber, jobholder, laborer, laborers,
   laboring man, linendrapers, lower classes, lower middle class,
   lower orders, lumpen proletariat, menial, middle class,
   middle orders, migrant, moiler, navvy, office temporary,
   ordinary people, peasantry, peon, plain folks, plain people,
   proletarian, proletariat, rank and file, roustabout,
   salaried worker, self-employed person, servant, shopkeepers,
   slavey, small tradesmen, stiff, temporary, the lower cut,
   the other half, the third estate, toilers, toiling class,
   upper middle class, vulgus, wage earner, wage slave, wageworker,
   worker, workgirl, workhand, workhorse, working class, working girl,
   working people, workingman, workingwoman, workman