Inactivity means the state of not doing anything or not being active. When you experience a period of inactivity, you're not moving, working, or taking action. A computer might go into sleep mode after ten minutes of inactivity, meaning no one has touched the keyboard or moved the mouse. A sports injury might force a player into inactivity, keeping them on the sidelines instead of on the field.

Inactivity isn't always bad. Sometimes your body needs rest, and a period of inactivity after intense exercise helps your muscles recover. But too much inactivity can cause problems. Muscles get weaker when they're not used, and skills get rusty without practice. Students might find that summer inactivity makes math harder when school starts again.

The word suggests a lack of motion or effort. A dormant volcano shows inactivity because it's not erupting. A neglected garden shows inactivity because no one's been tending it. Sometimes inactivity is a choice, like deciding to do nothing on a lazy Saturday. Other times it's forced on you, like being stuck inside during a storm. The key difference between inactivity and simply resting is that rest is purposeful and temporary, while inactivity suggests a longer stretch of doing nothing.