Crabby means grumpy, irritable, or easily annoyed. When someone is crabby, they snap at others over small things, complain more than usual, and generally seem unhappy about everything. Your normally cheerful friend might act crabby after a bad night's sleep, responding to simple questions with short, annoyed answers.

The word comes from comparing someone's mood to a crab's behavior: crabs scuttle sideways, wave their pincers defensively, and seem ready to pinch anything that comes near. A crabby person can act similarly defensive and prickly.

Everyone feels crabby sometimes. You might wake up crabby because you're tired, or become crabby when you're hungry (some people call this being hangry). The important thing is recognizing when you're feeling this way. When your little brother asks a perfectly reasonable question and you find yourself snapping at him, that's a sign you're feeling crabby.

The word is informal and somewhat playful: calling someone crabby sounds gentler than calling them mean or angry. When your mom says “You're being a little crabby this morning,” she's pointing out your mood while acknowledging that it's probably temporary and that you're not normally like this.