Lethargic means having very little energy or enthusiasm, feeling slow and sluggish both physically and mentally. When you're lethargic, even simple tasks feel like they require tremendous effort. Getting out of bed feels like lifting a boulder. Focusing on homework becomes nearly impossible. Your body feels heavy, your mind feels foggy, and motivation seems to have completely disappeared.

People often feel lethargic when they're sick, haven't slept enough, or have been sitting around doing nothing for too long. After a big Thanksgiving meal, many people feel lethargic because their bodies are working hard to digest all that food. On extremely hot, humid days, the weather itself can make you feel lethargic and drowsy.

When you're truly lethargic, you can feel like you're in a fog, disconnected from your usual energy and alertness.

A lethargy is the state of being lethargic. Teachers can usually spot lethargy in their students: drooping eyelids, slumped shoulders, and that thousand-yard stare out the window. Rest can cure some lethargy, but sitting around doing nothing for days can actually make lethargy worse. Sometimes moving around, going outside, and getting your blood flowing again can help you feel less lethargic.