1. To work very hard or diligently on someone or something else's behalf. We have nearly 30 employees laboring for us at this company, and any decision we make will affect all of them as well! I labored for her political campaign for months, but the moment it was over I was brushed aside without so much as a fare thee well.

2. To work very hard or diligently in order to accomplish, achieve, or obtain something All of our volunteers labor for the betterment of people in need. The huge farming operation, which supplies states across the country, has been accused of forcing migrant workers to labor for only a few dollars an hour, far short of the national minimum wage.