Lethargy

SOPOR

This state of deep drowsiness often follows a heavy meal or prolonged sleep deprivation, sometimes described as a stupor.

"Lethargy" hints at a state of deep drowsiness or sluggishness, and "sopor" is a less common but precise word for that heavy, sleepy stupor. The clue plays it straight—no wordplay or tricks—just a direct synonym that fits the definition. If you’re familiar with Latin roots, "sopor" ties back to "sleep," reinforcing the idea of extreme tiredness. It’s a concise answer that matches the clue’s tone without any hidden twists.