WordNet (r) 3.0 (2006):

putterer
    n 1: a person who putters about [syn: putterer, potterer]

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "putterer":
   Sunday painter, amateur, clock watcher, coquet, dabbler, dallier,
   dawdle, dawdler, diddler, dilettante, dillydallier, do-nothing,
   dolittle, doodler, faineant, flirt, fribble, gentleman of leisure,
   goldbrick, goldbricker, goof-off, idler, laggard, lingerer, loafer,
   loiterer, loller, lotus-eater, lounger, lubber, mope, moper,
   piddler, potterer, slouch, sloucher, slug, sluggard, smatterer,
   stick-in-the-mud, time killer, time waster, trifler,
   waiter on Providence