overwork

v. t.

  1. To work beyond the strength; to cause to labor too much or too long; to tire excessively; as, to overwork a horse.
  2. To fill too full of work; to crowd with labor.
  3. To decorate all over.
  4. To work too much, or beyond one's strength.

n.

  1. Work in excess of the usual or stipulated time or quantity; extra work; also, excessive labor.