vigorous

This word carries a sense of powerful, healthy vitality. It suggests a level of energy that is not just high, but active and purposeful. When describing a person, it implies a robust physical constitution and an alert, spirited disposition.

In professional or argumentative contexts, it shifts from physical strength to intellectual intensity. A vigorous defense or a vigorous protest indicates a firm, uncompromising, and energetic effort to persuade or resist, rather than a passive or mild response.