Run riot Definition 1 of 2Pro Tip 1/3Lack of Control Indicates a situation where people are losing their usual social or moral constraints. After the football match, hooligans ran riot in the streets. Pro Tip 2/3Child Behavior Commonly used to describe unruly behavior of children, often playful and noisy. The classroom was in chaos; the kids ran riot during the break. Pro Tip 3/3Emotional Connotation Suggests a negative reaction to a lack of structure or discipline. Without strict guidelines, the meeting ran riot and nothing got done.