The Collaborative International Dictionary of English v.0.48:

expelling \expelling\ n.
   any of several bodily processes by which substances go out of
   the body.

   Syn: discharge, emission.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Expel \Ex*pel"\, v. t. [imp. & p. p. Expelled, p. pr. & vb.
   n.. Expelling.] [L. expellere, expulsum; ex out + pellere
   to drive: cf.F. expeller. See Pulse a beat.]
   1. To drive or force out from that within which anything is
      contained, inclosed, or situated; to eject; as, to expel
      air from a bellows.
      [1913 Webster]

            Did not ye . . . expel me out of my father's house?
                                                  --Judg. xi. 7.
      [1913 Webster]

   2. To drive away from one's country; to banish.
      [1913 Webster]

            Forewasted all their land, and them expelled.
                                                  --Spenser.
      .
      [1913 Webster]

            He shall expel them from before you . . . and ye
            shall possess their land.             --Josh. xxiii.
                                                  5.
      [1913 Webster]

   3. To cut off from further connection with an institution of
      learning, a society, and the like; as, to expel a student
      or member.
      [1913 Webster]

   4. To keep out, off, or away; to exclude. "To expel the
      winter's flaw." --Shak.
      [1913 Webster]

   5. To discharge; to shoot. [Obs.]
      [1913 Webster]

            Then he another and another [shaft] did expel.
                                                  --Spenser.
      .

   Syn: To banish; exile; eject; drive out. See Banish.
        [1913 Webster]

WordNet (r) 3.0 (2006):

expelling
    n 1: any of several bodily processes by which substances go out
         of the body; "the discharge of pus" [syn: discharge,
         emission, expelling]