The Collaborative International Dictionary of English v.0.48:

Squalor \Squa"lor\ (skw[=a]"l[^o]r), n. [L., fr. squalere to be
   foul or filthy.]
   Squalidness; foulness; filthiness; squalidity.
   [1913 Webster]

         The heterogeneous indigent multitude, everywhere
         wearing nearly the same aspect of squalor. --I. Taylor.
   [1913 Webster]

         To bring this sort of squalor among the upper classes.
                                                  --Dickens.
   [1913 Webster]

WordNet (r) 3.0 (2006):

squalor
    n 1: sordid dirtiness [syn: sordidness, squalor,
         squalidness]

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "squalor":
   abjectness, abominableness, atrociousness, awfulness, baseness,
   beastliness, beggarliness, bestiality, blowziness, brutality,
   carelessness, chintziness, contemptibility, contemptibleness,
   crumminess, debasement, degradation, depravity, despicableness,
   detestableness, direness, disgustingness, dowdiness, dreadfulness,
   egregiousness, enormity, execrableness, filth, foulness,
   frowziness, frumpishness, fulsomeness, grossness, grubbiness,
   hatefulness, heinousness, horribleness, infamousness, littleness,
   loathsomeness, looseness, lousiness, lowness, meanness, messiness,
   miserableness, monstrousness, nastiness, nefariousness, negligence,
   noisomeness, notoriousness, obnoxiousness, odiousness,
   offensiveness, outrageousness, paltriness, pettiness, pokiness,
   poorness, rankness, repulsiveness, rottenness, scabbiness,
   scandalousness, scrubbiness, scruffiness, scumminess, scurviness,
   seediness, shabbiness, shamefulness, shoddiness, slatternliness,
   slipshodness, sloppiness, slovenliness, slovenry, slumminess,
   sluttishness, smallness, sordidness, squalidity, squalidness,
   tackiness, tawdriness, terribleness, the pits, uncleanness,
   unneatness, untidiness, vileness, worthlessness, wretchedness