How would you describe someone who is "indefatigable"?

To describe someone who is "indefatigable," the term captures the essence of a person who demonstrates an unwavering energy and persistence, especially in the face of difficulties. This quality reflects the ability to remain tireless and enthusiastic in their actions, showing sustained effort and commitment over time. Such a person does not easily succumb to fatigue or discouragement, which aligns perfectly with the label of someone showing sustained enthusiastic action.

The other choices do not align with this meaning. Someone who is exhausted and weary would be the opposite of indefatigable, as they would lack energy and the ability to persist. Being apathetic and indifferent indicates a lack of interest or motivation, which sharply contrasts the enthusiastic nature implied by being indefatigable. Similarly, describing someone as inconsistent and unreliable suggests a failure to maintain steady or dependable behavior, further differing from the persistent reliability that characterizes an indefatigable individual. Therefore, the choice that accurately reflects the meaning is the one pointing to sustained enthusiastic action.