Source : Webster's Revised Unabridged Dictionary (1913)

Slough \Slough\, obs.
   imp. of {Slee}, to slay. Slew. --Chaucer.

Slough \Slough\, n. [OE. slugh, slouh; cf. MHG. sl?ch the skin
   of a serpent, G. schlauch a skin, a leather bag or bottle.]
   1. The skin, commonly the cast-off skin, of a serpent or of
      some similar animal.

   2. (Med.) The dead mass separating from a foul sore; the dead
      part which separates from the living tissue in
      mortification.

Slough \Slough\, a.
   Slow. [Obs.] --Chaucer.

Slough \Slough\, n. [OE. slogh, slough, AS. sl[=o]h a hollow
   place; cf. MHG. sl[=u]ch an abyss, gullet, G. schlucken to
   swallow; also Gael. & Ir. sloc a pit, pool. ditch, Ir. slug
   to swallow. Gr. ????? to hiccough, to sob.]
   1. A place of deep mud or mire; a hole full of mire.
      --Chaucer.

            He's here stuck in a slough.          --Milton.

   2. [Pronounced sl[=oo].] A wet place; a swale; a side channel
      or inlet from a river.

   Note: [In this sense local or provincial; also spelt {sloo},
         and {slue}.]

   {Slough grass} (Bot.), a name in the Mississippi valley for
      grasses of the genus {Muhlenbergia}; -- called also {drop
      seed}, and {nimble Will}.

Slough \Slough\, v. i. [imp. & p. p. {Sloughed}; p. pr. & vb. n.
   {Sloughing}.] (Med.)
   To form a slough; to separate in the form of dead matter from
   the living tissues; -- often used with off, or away; as, a
   sloughing ulcer; the dead tissues slough off slowly.

Slough \Slough\, v. t.
   To cast off; to discard as refuse.

         New tint the plumage of the birds, And slough decay
         from grazing herds.                      --Emerson.

Source : WordNet®

slough
     n 1: necrotic tissue; a mortified or gangrenous part or mass
          [syn: {gangrene}, {sphacelus}]
     2: a hollow filled with mud
     3: a stagnant swamp (especially as part of a bayou)
     4: any outer covering that can be shed or cast off (such as the
        cast-off skin of a snake)

slough
     v : cast off hair, skin, horn, or feathers; "out dog sheds every
         Spring" [syn: {shed}, {molt}, {exuviate}, {moult}]