Grumpiness is a mood where someone feels irritable, cranky, and quick to complain or snap at others. When you're grumpy, little annoyances that wouldn't normally bother you suddenly feel unbearable. Your sister's humming might sound too loud, your breakfast might taste wrong, and even sunshine seems too bright.

Everyone experiences grumpiness sometimes. You might wake up grumpy after a bad night's sleep, or become grumpy when you're hungry (some people call this being “hangry”). Adults get grumpy when they're stressed or tired. The key thing about grumpiness is that it's temporary: it passes once you rest, eat, or once whatever was bothering you gets resolved.

The tricky part about grumpiness is that it can spread. When you're grumpy, you might snap at your friend, who then gets grumpy and snaps at someone else. If you notice you're feeling grumpy, sometimes just recognizing it helps: “I'm grumpy because I'm tired, not because my brother did anything wrong.”

A grump is someone who seems to stay grumpy all the time, turning crankiness into a big part of their personality. Most people don't enjoy being around a permanent grump, which is why noticing when you're having a grumpy moment can be helpful.