Which word refers to a state of being affected by lethargy, characterized by sluggishness and apathy?

The term "lethargic" directly captures the essence of a state associated with lethargy, which is characterized by a lack of energy and enthusiasm. When someone is described as lethargic, it indicates that they are experiencing significant sluggishness and a general sense of apathy toward their environment or activities. This word effectively conveys the profound sense of tiredness and lack of motivation that defines lethargy.

In contrast, while "apathetic" does convey a sense of lack of interest, it does not inherently include the aspect of sluggishness that "lethargic" encompasses. "Flippant" describes a casual or dismissive attitude, which is unrelated to the states of energy or enthusiasm. Additionally, "pallid" generally refers to a lack of color or liveliness, often in a physical sense, rather than a state of mental sluggishness or apathy. Therefore, "lethargic" is the most appropriate choice for describing a state of being affected by both sluggishness and apathy.