What term is used to describe a state of being strong and healthy?

The term that describes a state of being strong and healthy is "robust." This word is commonly used to refer to someone or something that is vigorous, sturdy, or resilient. In the context of health, a robust individual implies not only physical strength but also a good immune system and overall vitality.

Understanding this term can be particularly valuable in various fields, including health and fitness, where the goal is often to achieve or maintain a robust state of well-being. The other options do not convey this same meaning; terms like "feckless," "foolhardy," and "glib" highlight characteristics that are generally more negative or unrelated to strength and health. Therefore, "robust" stands out as the most fitting choice for describing an optimized state of health and strength.