The Collaborative International Dictionary of English v.0.48:

crappy \crap"py\ (kr[a^]p"p[y^]), a.
   of very poor quality. [slang]

   Syn: lousy; crummy. [PJC]

WordNet (r) 3.0 (2006):

crappy
    adj 1: very bad; "a lousy play"; "it's a stinking world" [syn:
           icky, crappy, lousy, rotten, shitty,
           stinking, stinky]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "crappy":
   amiss, bad, barfy, bum, cheesy, creepy, crummy, dirty, disgusting,
   dissatisfactory, dungy, excremental, excrementary, fecal, feculent,
   fetid, filthy, flyblown, foul, gloppy, godawful, goshawful, grim,
   gunky, hairy, icky, maggoty, malodorous, mephitic, mucky, nasty,
   nauseating, odious, ordurous, poor, puky, punk, putrid, rank,
   repulsive, rotten, scabby, scatologic, scatological, scummy,
   scurfy, shitty, slabby, slimy, sloppy, sloshy, sludgy, slushy,
   sposhy, stercoraceous, stercoral, stinking, stinky, unsatisfactory,
   up, urinary, urinative, vile, vomity, wormy, wrong, yecchy