The Collaborative International Dictionary of English v.0.48:

Augean \Au*ge"an\, a.
   1. (Class. Myth.) Of or pertaining to Augeus, king of Elis,
      whose stable contained 3000 oxen, and had not been cleaned
      for 30 years. Hercules cleansed it in a single day.
      [1913 Webster]

   2. Hence: Exceedingly filthy or corrupt.
      [1913 Webster]

   Augean stable (Fig.), an accumulation of corruption or
      filth almost beyond the power of man to remedy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Augean
    adj 1: extremely filthy from long neglect