Boisterous means noisy, energetic, and full of rough, cheerful enthusiasm. A boisterous crowd at a basketball game cheers loudly, jumps around, and creates an atmosphere of wild excitement. A group of boisterous children might race through the playground, laughing and shouting at the top of their lungs.

The word captures a specific kind of energy: joyfully, almost uncontrollably loud. A boisterous puppy barks while bouncing around the room, knocks things over with its wagging tail, and greets everyone with overwhelming enthusiasm. A boisterous laugh isn't polite or quiet; it bursts out and fills the room.

While boisterous usually describes happy, high-spirited behavior, it can sometimes feel like too much. A boisterous dinner table might be fun at home but inappropriate at a fancy restaurant. A teacher might need to calm down a boisterous classroom before a lesson can begin. The word suggests energy that's genuine and good-natured, even when it needs to be toned down a notch.