The Collaborative International Dictionary of English v.0.48:

Lousy \Lous"y\, a.
   1. Infested with lice.
      [1913 Webster]

   2. Mean; contemptible; as, lousy knave. [informal]
      [1913 Webster]

            Such lousy learning as this is.       --Bale.

   3. Very bad; as, to feel lousy; to do a lousy job.
      [PJC]

WordNet (r) 3.0 (2006):

lousy
    adj 1: very bad; "a lousy play"; "it's a stinking world" [syn:
           icky, crappy, lousy, rotten, shitty,
           stinking, stinky]
    2: infested with lice; "burned their lousy clothes"
    3: vile; despicable; "a dirty (or lousy) trick"; "a filthy
       traitor" [syn: dirty, filthy, lousy]

Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "lousy":
   abominable, alive with, arrant, atrocious, awful, bad, base,
   beastly, beneath contempt, beset, blameworthy, brutal,
   contemptible, deplorable, despicable, detestable, dire, dirty,
   disgusting, dreadful, egregious, enormous, fetid, filthy, flagrant,
   foul, fulsome, grievous, gross, grubby, hateful, heinous, horrible,
   horrid, infamous, inferior, infested, lamentable, loathsome, low,
   low-quality, mean, miserable, monstrous, nasty, nefarious, noisome,
   notorious, obnoxious, odious, offensive, outrageous, pedicular,
   pediculous, pitiable, pitiful, plagued, poor, rank, ratty, ravaged,
   regrettable, reprehensible, repulsive, rotten, sad, scandalous,
   schlock, scurvy, second-rate, shabby, shameful, shocking, shoddy,
   sordid, squalid, teeming, terrible, too bad, unclean, vicious,
   vile, villainous, woeful, wormy, worst, worthless, wretched