Use too much

• The act working too much or too long
• Work excessively hard

WordNet Word definitions in WordNet
n. the act working too much or too long; "he became ill from overwork" [syn: overwork ]

Wiktionary Word definitions in Wiktionary
vb. (present participle of overwork English)

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Overwork \O`ver*work"\, v. t. [imp. & p. p. Overworked or Overwrought ; p. pr. & vb. n. Overworking .] To work beyond the strength; to cause to labor too much or too long; to tire excessively; as, to overwork a horse. To fill too full of work; to crowd ...