yawn

v. i.

  1. To open the mouth involuntarily through drowsiness, dullness, or fatigue; to gape; to oscitate.
  2. To open wide; to gape, as if to allow the entrance or exit of anything.
  3. To open the mouth, or to gape, through surprise or bewilderment.
  4. To be eager; to desire to swallow anything; to express desire by yawning; as, to yawn for fat livings.

n.

  1. An involuntary act, excited by drowsiness, etc., consisting of a deep and long inspiration following several successive attempts at inspiration, the mouth, fauces, etc., being wide open.
  2. The act of opening wide, or of gaping.
  3. A chasm, mouth, or passageway.