Obstreperous means noisy, unruly, and difficult to control. An obstreperous student might shout out answers, refuse to stay seated, and disrupt the whole classroom despite the teacher's repeated requests for quiet. An obstreperous crowd at a concert might push and shove, ignoring security guards trying to maintain order.

The word describes more than simple loudness or energy. An obstreperous person actively resists control or authority, often in a boisterous, attention-grabbing way. A puppy that won't stop barking and jumping might be called obstreperous. So might a group of protesters who deliberately try to interrupt a meeting by chanting and refusing to leave when asked.

You'll often see obstreperous paired with words like crowd, behavior, or child. It carries a tone of frustration: someone describing another person as obstreperous usually wishes that person would settle down and cooperate. While enthusiasm and energy can be wonderful qualities, obstreperous behavior crosses the line into disruptive territory, making it hard for anyone else to focus, communicate, or get things done.