Source : Webster's Revised Unabridged Dictionary (1913)

Dirtiness \Dirt"i*ness\, n.
   The state of being dirty; filthiness; foulness; nastiness;
   baseness; sordidness.

Source : WordNet®

dirtiness
     n 1: the state of being unsanitary [syn: {uncleanness}] [ant: {cleanness}]
     2: the state of containing dirty impurities
     3: obscenity in speech or writing [syn: {smuttiness}]