What does 'languorous' refer to in terms of vitality?

The term 'languorous' describes a state characterized by a lack of energy and vitality, often conveying a sense of lethargy or sluggishness. It is used to depict a feeling of indolence or a dreamy, tired state where one feels weak or weary. This aligns perfectly with the choice indicating a lack of spirit or liveliness, capturing the essence of what 'languorous' implies.

In contrast, the other options present states that are distinctly opposite to the meaning of 'languorous.' Being described as extremely energetic suggests an abundance of vitality, while excessively mournful and unexpectedly cheerful both imply more emotional intensity that does not reflect the slow-moving, listless quality associated with languor. Thus, the answer that conveys the absence of vigor aligns seamlessly with the meaning of the word.