An instinct is a natural behavior or ability that an animal or person is born with, rather than something learned through practice or teaching. When a spider spins its first web, it doesn't need lessons: instinct guides its movements. When a newborn baby turns its head to feed, that's instinct at work too.

Think of instinct as built-in programming. Birds don't take flying lessons from their parents: they have an instinct that tells them how to move their wings. Salmon swimming upstream to spawn, squirrels burying nuts for winter, and cats pouncing on moving objects are all instinctive behaviors that happen automatically.

Humans have instincts too. You pull your hand away from something hot without thinking. You duck when something flies toward your face. These protective reactions happen faster than thought because they're instinctive.

The word also describes a natural sense or feeling about something. When you meet someone new and immediately feel comfortable or uneasy, you might call that an instinct. A good teacher might have an instinct for knowing when students are confused, even if they don't say anything. Your instincts can guide you toward good decisions, though unlike animal instincts, human instincts aren't always right. That's why we also use reason and experience alongside our instincts.