The Collaborative International Dictionary of English v.0.48:

Malingerer \Ma*lin"ger*er\, n. [F. malingre sickly, weakly,
   prob. from mal ill + OF. heingre, haingre, thin, lean,
   infirm, fr. L. aeger.]
   In the army, a soldier who feigns himself sick, or who
   induces or protracts an illness, in order to avoid doing his
   duty; hence, in general, one who shirks his duty by
   pretending illness or inability.
   [1913 Webster]

WordNet (r) 3.0 (2006):

malingerer
    n 1: someone shirking their duty by feigning illness or
         incapacity [syn: malingerer, skulker, shammer]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "malingerer":
   blagueur, bluff, bluffer, bungler, charlatan, clock watcher,
   disregarder, dodger, eye-servant, fake, faker, fourflusher, fraud,
   goldbrick, goldbricker, goof-off, humbug, idler, ignorer,
   impersonator, impostor, mountebank, neglecter, negligent,
   old soldier, phony, poser, poseur, pretender, procrastinator,
   quack, quacksalver, quackster, ringer, saltimbanco, sham, shammer,
   shirk, shirker, skulk, skulker, slacker, sloven, slut, soldier,
   tax dodger, trifler, truant, waiter on Providence, welsher