overwork

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To force to work too hard or too long.
• intransitive verb To rework to excess.
• intransitive verb To use too often.
• intransitive verb To decorate the entire surface of.
• intransitive verb To work too long or too hard.
• noun Excessive work.

from The Century Dictionary.

• noun A superstructure.
• noun Excessive work or labor; work or labor that exceeds the strength or capacity of the individual or endangers his health.
• noun Work done beyond the amount stipulated; work done in overhours or overtime.
• To cause to work too hard; cause to labor too much; impose too much work upon; wear out by overwork: often used reflexively.

from the GNU version of the Collaborative International Dictionary of English.

• noun Work in excess of the usual or stipulated time or quantity; extra work; also, excessive labor.
• transitive verb To work beyond the strength; to cause to labor too much or too long; to tire excessively.
• transitive verb To fill too full of work; to crowd with labor.
• transitive verb To decorate all over.
• intransitive verb To work too much, or beyond one's strength.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb transitive To make (someone) work too hard.
• verb intransitive To work too hard.
• noun excessive work

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb work excessively hard
• noun the act of working too much or too long
• verb use too much