Jittery means nervously jumpy or shaky, like you can't quite hold still. When you're jittery, you might fidget with your pencil, tap your feet, bounce your knee, or feel like butterflies are doing loop-de-loops in your stomach.

You might feel jittery before giving a presentation in front of the class, or while waiting to hear if you made the team. Your hands might feel a little shaky, your heart might beat faster, and you might have trouble sitting still. Some people get jittery after drinking too much soda or eating too much sugar, which can make them feel wired and unable to settle down.

The word captures both the physical and emotional sides of nervousness. A jittery squirrel darting around a park looks as anxious as it feels. Coffee makes some people jittery because caffeine speeds up their nervous system. The opposite of jittery would be calm, steady, or relaxed.

Notice that jittery isn't the same as scared. You can feel jittery about something exciting, like a field trip you've been looking forward to for weeks. It's that restless, keyed-up energy that makes you feel like you need to move.