When something is remunerative, it means people get paid for it. Your job is remunerative, and if your research into new farming methods leads to a big government contract, then that also could be called remunerative.
Remunerative can also mean that something generates a lot of money, like the remunerative ice cream truck that appears at the park entrance on the hottest days of summer. In Latin, munus and muner- mean "gift." Re- means "again," emphasizing that the reward keeps coming, whether it is a weekly paycheck or something that continues to generate sales, like the ice cream truck.