The Collaborative International Dictionary of English v.0.48:

Turbidity \Tur*bid"i*ty\, n.
   Turbidness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

turbidity
    n 1: muddiness created by stirring up sediment or having foreign
         particles suspended [syn: turbidity, turbidness]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "turbidity":
   adiaphanousness, agitation, bluster, bobbery, boil, boiling,
   brouhaha, bustle, churn, cloudiness, commotion, conturbation,
   darkness, dimness, dirtiness, discomposure, disorder, disquiet,
   disquietude, disturbance, ebullition, embroilment, excitement,
   ferment, fermentation, fever, feverishness, fidgets, flap, flurry,
   fluster, flutteration, foment, fume, fuss, hubbub, hurly-burly,
   imperviousness to light, inquietude, intransparency, jitters,
   jumpiness, maelstrom, malaise, miriness, moil, muckiness,
   muddiness, nerviness, nervosity, nervousness, obscurity, ooziness,
   opacity, opaque, opaqueness, perturbation, restlessness, roil,
   roiledness, rout, row, seethe, seething, slabbiness, slobbiness,
   sloppiness, sloshiness, sludginess, slushiness, squashiness,
   squelchiness, stir, swirl, to-do, trepidation, trepidity, tumult,
   tumultuation, turbidness, turbulence, turmoil, twitter, unease,
   unrest, upset