Source : Webster's Revised Unabridged Dictionary (1913)

Muddy \Mud"dy\, a. [Compar. {Muddier}; superl. {Muddiest}.]
   1. Abounding in mud; besmeared or dashed with mud; as, a
      muddy road or path; muddy boots.

   2. Turbid with mud; as, muddy water.

   3. Consisting of mud or earth; gross; impure.

            This muddy vesture of decay.          --Shak.

   4. Confused, as if turbid with mud; cloudy in mind; dull;
      stupid; also, immethodical; incoherent; vague.

            Cold hearts and muddy understandings. --Burke.

            Dost think I am so muddy, so unsettled. --Shak.

   5. Not clear or bright. --Swift.

Muddy \Mud"dy\, v. t. [imp. & p. p. {Muddied}; p. pr. & vb. n.
   {Muddying}.]
   1. To soil with mud; to dirty; to render turbid.

   2. Fig.: To cloud; to make dull or heavy. --Grew.

Source : WordNet®

muddy
     adj 1: (of soil) soft and watery; "the ground was boggy under
            foot"; "a marshy coastline"; "miry roads"; "wet mucky
            lowland"; "muddy barnyard"; "quaggy terrain"; "the
            sloughy edge of the pond"; "swampy bayous" [syn: {boggy},
             {marshy}, {miry}, {mucky}, {quaggy}, {sloughy}, {swampy}]
     2: dirty and messy; covered with mud or muck; "muddy boots"; "a
        mucky stable" [syn: {mucky}]
     3: (of color) discolored by impurities; not bright and clear;
        "dirty" is often used in combination; "a dirty (or dingy)
        white"; "the muddied gray of the sea"; "muddy colors";
        "dirty-green walls"; "dirty-blonde hair" [syn: {dirty}, {dingy},
         {muddied}]
     4: (of especially liquids) clouded as with sediment; "a cloudy
        liquid"; "muddy coffee"; "murky waters" [syn: {cloudy}, {mirky},
         {murky}, {turbid}]
     [also: {muddied}, {muddiest}, {muddier}]

muddy
     v 1: dirty with mud [syn: {muddy up}]
     2: cause to become muddy; "These data would have muddied the
        prediction"
     3: make turbid; "muddy the water"
     [also: {muddied}, {muddiest}, {muddier}]