Anything that's part-time is done less often than is typical or average. If you're sick of working full-time hours, try working part-time.
Part-time works as an adjective or an adverb, to describe things that don't take up as much time as you might expect, just part of a day or part of a week. If you're a part-time bus driver, you might do it twenty hours each week, in between classes. You could also call yourself a part-time student, or say that you study sociology part-time.