Which word best describes behavior that is unruly or uncontrollable?

The word "rambunctious" is the most fitting choice to describe behavior that is unruly or uncontrollable. It captures the essence of being energetic, boisterous, and often difficult to manage. This term is frequently used to describe children or animals that exhibit lively, disorderly behavior, which correlates directly with the idea of being uncontrollable.

In contrast, terms like "tame," "disciplined," and "composed" all suggest a level of control and orderliness. "Tame" refers to domesticated or manageable behavior, often in relation to animals or situations that are not wild. "Disciplined" implies a sense of control and adherence to rules or structure, while "composed" indicates calmness and a steady demeanor. None of these words convey the chaotic and spirited nature associated with being unruly, which is why "rambunctious" stands out as the most appropriate description.