vigor

This term conveys a sense of robust, active energy that is both physical and mental. It suggests a state of being fully alive and capable, often associated with youth or a sudden recovery of strength. While it can describe a person's health, it frequently describes the manner in which a task is performed, implying a high level of intensity and drive. In a professional or political context, the word shifts from biological health to operational force. It describes the persistence and power applied to a goal, such as pursuing a legal case or implementing a policy, where the focus is on the strength of the effort rather than the physical stamina of the individual.