The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sloughing \Slough"ing\, n. (Zool.)
   The act of casting off the skin or shell, as do insects and
   crustaceans; ecdysis.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sloughing
    n 1: the process whereby something is shed [syn: shedding,
         sloughing]