When Joseph R. DesJardins discusses the liberal model of work in his An Introduction to Business Ethics, he notes that people who hold this theory believe that workers should be free to choose their own goals. This model recognizes that sometimes people perform jobs that they don't especially enjoy (or even hate) because they have to earn money to support themselves and their families.
The liberal model of work, therefore, does not hold that all human work must be directed toward some high end of human fulfillment, but it does allow that work can be meaningful when work gives a person the “ability to make free and autonomous decisions” about his or her own life. According to this model, then, meaningful work allows workers to pursue “primary goods” like individual freedom and mental and physical health along with whatever other goods and ends that workers identify as important to them.
In this model, meaningful work is partly determined by the worker's goals and partly determined by the protection of the primary goods. So a job as a construction worker can be greatly meaningful to someone who is happy to be employed so he can provide for his family and spend some leisure time with them while a job as a college professor can lack meaning if is so stressful that it is making the worker sick due to stress (and thereby not protecting the primary good of health).