oscitancy

from WordNet (r) 3.0 (2006)

oscitancy
    n 1: drowsiness and dullness manifested by yawning [syn:
         {oscitancy}, {oscitance}]
    2: an involuntary intake of breath through a wide open mouth;
       usually triggered by fatigue or boredom; "he could not
       suppress a yawn"; "the yawning in the audience told him it
       was time to stop"; "he apologized for his oscitancy" [syn:
       {yawn}, {yawning}, {oscitance}, {oscitancy}]

from The Collaborative International Dictionary of English v.0.48

Oscitancy \Os"ci*tan*cy\, n. [See {Oscitant}.]
   [1913 Webster]
   1. The act of gaping or yawning.
      [1913 Webster]

   2. Drowsiness; dullness; sluggishness. --Hallam.
      [1913 Webster]

            It might proceed from the oscitancy of transcribers.
                                                  --Addison.
      [1913 Webster]