The Collaborative International Dictionary of English v.0.48:

goldbrick \gold"brick`\ n.
   an idle worthless person. [slang]

   Syn: goof-off, ne'er-do-well, good-for-nothing,
        good-for-naught.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

goldbrick
    n 1: a soldier who performs his duties without proper care or
         effort
    2: an idle worthless person [syn: goldbrick, goof-off, ne
       'er-do-well, good-for-nothing, no-account, good-for-
       naught]
    3: a brick-shaped block that looks like gold but is not
    4: anything that is supposed to be valuable but turns out to be
       worthless
    v 1: deprive of by deceit; "He swindled me out of my
         inheritance"; "She defrauded the customers who trusted
         her"; "the cashier gypped me when he gave me too little
         change" [syn: victimize, swindle, rook, goldbrick,
         nobble, diddle, bunco, defraud, scam, mulct,
         gyp, gip, hornswoggle, short-change, con]
    2: avoid (one's assigned duties); "The derelict soldier shirked
       his duties" [syn: fiddle, shirk, shrink from,
       goldbrick]

Moby Thesaurus II by Grady Ward, 1.0:

116 Moby Thesaurus words for "goldbrick":
   abandon, boiler room, bucket shop, bum, bunco game, bungler,
   clock watcher, con game, confidence game, cut, dallier, dawdle,
   dawdler, diddler, dillydallier, disregarder, do-nothing, dodge,
   dodger, dog it, dolittle, doodler, drone, duck, duck duty,
   eye-servant, faineant, foot-dragger, gentleman of leisure,
   get out of, goldbricker, goof off, goof-off, idler, ignorer, jump,
   laggard, laze, lazy, leave, leave loose ends, leave undone,
   let alone, let be, let dangle, let go, lie-abed, lingerer, loaf,
   loafer, loiter, loiterer, loll, loller, lotus-eater, lounge,
   lounger, lubber, malinger, malingerer, miss, mope, moper,
   neglecter, negligent, not pull fair, old soldier, omit, pass over,
   pass up, plodder, potterer, pretermit, procrastinate,
   procrastinator, putterer, shell game, shirk, shirker, skin game,
   skip, skulk, skulker, slack, slacker, sleepyhead, slide out of,
   slinker, slip out of, slouch, sloucher, sloven, slow goer,
   slow-foot, slowbelly, slowpoke, slug, sluggard, slut, snail,
   sneak out of, soldier, spiv, stick-in-the-mud, tax dodger,
   thimblerig, thimblerigging, time killer, time waster, tortoise,
   trifle, trifler, truant, waiter on Providence, welsh, welsher