A robust economy is like a well-fed man, he or it is thriving, and has enjoyed success, while at the same time, is positive and optimistic for more earnings in the future (or meals in the case of the well-fed man). Robust means healthy, full of life. One synonym is sanguine. A robust economy is diversified, hungry, and succeeding at business, and most likely a robust economy leads to further development inside the country.... better schools, and highways, and infrastructure, perhaps more policemen, and a better quality of life for all or some citizens.