What does lethargy mean?
Lethargy is a noun for a state of unusual sluggishness, drowsiness, or lack of energy. It can refer to physical and mental symptoms, such as fatigue, difficulty concentrating, and a reluctance to move or act. It also has a figurative use for organizations, institutions, or communities that show little activity, initiative, or willingness to respond to problems. The word often suggests more than ordinary tiredness: lethargy implies a lingering or conspicuous dullness that affects behavior or performance. In medical contexts, it may describe reduced responsiveness or alertness. Figuratively, descriptions of political, economic, or organizational lethargy emphasize stagnation and a lack of momentum. Its vivid history comes from ancient Greek roots associated with forgetfulness and the failure to stir, making the modern word especially apt for describing both bodily inactivity and a metaphorical inability to awaken to action.
nounA state of sluggishness or drowsiness marked by a lack of physical energy, alertness, or willingness to act. Figuratively, it refers to a prolonged lack of activity, progress, or responsiveness.
- A state of physical or mental sluggishness, often involving drowsiness, reduced energy, or difficulty concentrating.
- A figurative lack of activity, initiative, or responsiveness, especially in a person, organization, or system.
"A long, humid afternoon induced a deep lethargy that made even simple tasks feel burdensome."
"He blamed his lethargy on a combination of jet lag and a week of poor sleep."
"The committee's lethargy allowed important problems to remain unresolved for months."
Usually used as an uncountable singular noun, especially for a state or condition; the plural is rare and more likely to refer to separate instances or types of lethargy.
"The report describes recurring lethargies in workers exposed to extreme heat."
Lethargy is not merely tiredness: it is the conspicuous absence of the energy needed to move, think, or respond.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does lethargy come from?
Lethargy comes through Latin lethargia from Ancient Greek lēthargos, meaning “forgetful” or “apathetic,” a term associated with the Greek roots for forgetfulness and the failure to stir. The word entered English in the early 17th century, initially in medical writing. Its Greek ancestry connects it with lethargic and lethargically, which preserve the same idea of sluggishness or apathy.
Related word forms
How lethargy is actually used
The word is formal and generally conveys a more persistent or pronounced state than ordinary tiredness. It can describe physical drowsiness, mental or emotional apathy, or, figuratively, institutional and social inactivity.
Easily confused with lethargy
Lethargy is the noun naming a state of sluggishness, while lethargic is the adjective describing a person, condition, or thing affected by that state.