What word can be used to describe a state of exhaustion or tiredness?

The term "weary" effectively describes a state of exhaustion or tiredness because it directly connotes feelings of fatigue and weariness often associated with prolonged physical or mental exertion. It captures the essence of being drained or lacking in energy, which aligns perfectly with the experience of tiredness.

In contrast, "alert" refers to being watchful and attentive, indicating a state of readiness and awareness, which is the opposite of exhaustion. "Energetic" describes a state of having or showing a lot of energy or enthusiasm, again emphasizing vitality rather than fatigue. Finally, "flourishing" suggests thriving or growing well, which connotes strength and vitality rather than weariness or tiredness. Therefore, the word "weary" is the most appropriate descriptor for a state of exhaustion.