The Collaborative International Dictionary of English v.0.48:

Turbid \Tur"bid\ (t[^u]r"b[i^]d), a. [L. turbidus, from turba
   tumult, disturbance, akin to turbare to disturb. See
   Trouble, and cf. Disturb, Perturb.]
   1. Not clear; having suspended matter that scatters light
      passing through; having the lees or sediment disturbed;
      roiled; muddy; thick; -- used of liquids of any kind; as,
      turbid water; turbid wine.
      [1913 Webster]

            On that strong, turbid water, a small boat,
            Guided by one weak hand, was seen to float.
                                                  --Whittier.
      [1913 Webster]

   2. Disturbed; confused; disordered. " Such turbid intervals
      that use to attend close prisoners." --Howell.
      [1913 Webster]

WordNet (r) 3.0 (2006):

turbid
    adj 1: (of liquids) clouded as with sediment; "a cloudy liquid";
           "muddy coffee"; "murky waters" [syn: cloudy, muddy,
           mirky, murky, turbid]