Source : Webster's Revised Unabridged Dictionary (1913)

Morass \Mo*rass"\, n. [OE. marras, mareis (perh. through D.
   moeras), fr. F. marais, prob. from L. mare sea, in LL., any
   body of water; but perh. influenced by some German word. See
   {Mere} a lake, and cf. {Marsh}.]
   A tract of soft, wet ground; a marsh; a fen.

   {Morass ore}. (Min.) See {Bog ore}, under {Bog}.

Source : WordNet®

morass
     n : a soft wet area of low-lying land that sinks underfoot [syn:
          {mire}, {quagmire}, {quag}]