The Collaborative International Dictionary of English v.0.48:

Wastrel \Wast"rel\, n.
   1. Any waste thing or substance; as:
      (a) Waste land or common land. [Obs.] --Carew.
      (b) A profligate. [Prov. Eng.]
      (c) A neglected child; a street Arab. [Eng.]
          [1913 Webster]

   2. Anything cast away as bad or useless, as imperfect bricks,
      china, etc. [Obs. or Prov. Eng.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

wastrel
    n 1: someone who dissipates resources self-indulgently [syn:
         wastrel, waster]

Moby Thesaurus II by Grady Ward, 1.0:

113 Moby Thesaurus words for "wastrel":
   Arab, Bowery bum, bad lot, beach bum, beachcomber, beggar,
   beggarly fellow, big-time spender, black sheep, blackguard,
   blighter, bo, budmash, bum, bummer, caitiff, castaway, castoff,
   derelict, devil, discard, dissipater, dogie, drifter, drunkard,
   flotsam, flotsam and jetsam, foundling, gamin, gamine,
   good-for-naught, good-for-nothing, guttersnipe, hobo,
   homeless waif, human wreck, idler, jetsam, junk, knave, lagan,
   landloper, lazzarone, lecher, libertine, loafer, losel, lounger,
   lowlife, mauvais sujet, mean wretch, mucker, mudlark, no-good,
   orphan, pauvre diable, piker, pilgarlic, poor creature, poor devil,
   prodigal, prodigal son, profligate, ragamuffin, ragman, ragpicker,
   rake, rapscallion, rascal, refuse, reject, rip, rogue, roue,
   rounder, rubbish, sad case, sad sack, scalawag, scamp, scapegrace,
   scoundrel, ski bum, skid-row bum, spend-all, spender, spendthrift,
   squanderer, stiff, stray, street Arab, street urchin, sundowner,
   surf bum, swagman, swagsman, tatterdemalion, tennis bum, tramp,
   trash, truant, turnpiker, urchin, vag, vagabond, vagrant, vaurien,
   waif, waifs and strays, waster, wastethrift, worthless fellow,
   wretch