Fleeting describes something that lasts only a very short time before disappearing. A fleeting moment passes so quickly you barely notice it. A fleeting glimpse means you saw something for just an instant before it vanished from view.

Think of how a shooting star streaks across the night sky: you might spot it for only a second or two before it's gone. That's a fleeting sight. Or imagine catching the scent of fresh cookies as you walk past a bakery: the smell reaches you and then fades almost immediately. That pleasant experience was fleeting.

The word often carries a sense of something precious slipping away. A fleeting expression of happiness on someone's face tells you they felt joy for just a moment. Childhood itself can feel fleeting to parents as they watch their kids grow up seemingly overnight.

When something is fleeting, you can't hold onto it no matter how much you might want to. Summer vacation can feel fleeting. The perfect temperature of hot chocolate before it gets too cool is fleeting. Even success can feel fleeting if you don't take time to appreciate it. The word reminds us that some beautiful or important things pass quickly, which makes them all the more worth noticing while they're here.