plodder

from WordNet (r) 3.0 (2006)

plodder
    n 1: someone who walks in a laborious heavy-footed manner [syn:
         {trudger}, {plodder}, {slogger}]
    2: someone who works slowly and monotonously for long hours
       [syn: {plodder}, {slogger}]
    3: someone who moves slowly; "in England they call a slowpoke a
       slowcoach" [syn: {plodder}, {slowpoke}, {stick-in-the-mud},
       {slowcoach}]

from The Collaborative International Dictionary of English v.0.48

Plodder \Plod"der\, n.
   One who plods; a drudge.
   [1913 Webster]

from Moby Thesaurus II by Grady Ward, 1.0

33 Moby Thesaurus words for "plodder":
      beast of burden, dawdle, dawdler, drone, drudge, fag, foot-dragger,
      galley slave, goldbrick, goof-off, greasy grind, grind, grub, hack,
      laggard, lie-abed, lingerer, loiterer, procrastinator, slave,
      sleepyhead, slogger, slow goer, slow-foot, slowbelly, slowpoke,
      slug, sluggard, snail, stick-in-the-mud, swot, tortoise,
      workhorse

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