noun
lethargy
LETH-er-jee/ˈleθərdʒi/
A state of tiredness and sluggishness.
The woman's lethargy leaves her slumped over an untouched breakfast.

Etymology
Greek lēthargia meant “forgetfulness.” In English, the word denoted prolonged torpor or inactivity of body or mind, providing the bridge to its current sense of extreme tiredness or lack of energy.
In context
a violent fever intervened which the Physicians did all in their power to allay as soon as his reason returned a little Alexander aroused himself from his lethargy
More examples
- The summer heat brings on a wave of lethargy.
- Her usual energy returns as the lethargy fades.
- Persistent lethargy can make even simple chores feel difficult.
Forms
lethargy
lethargic adjective — Feeling tired, sluggish, and lacking energy.
lethargically adverb — In a slow manner lacking energy.
Similar words
- fatigue
- Emphasizes tiredness rather than sluggish movement or reduced activity.
- sluggishness
- Emphasizes slow movement or response, not necessarily feeling tired.