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To act in a chaotic manner. As soon as the alarm went off, everyone in the room ran riot.
run riotand run wild
Fig. to get out of control. The dandelions have run riot in our lawn. The children ran wild at the birthday party and had to be taken home.
1. If someone runs riot, they behave badly, sometimes violently, and in a way that is not controlled. My older sister Mandy had run riot so my parents were far stricter with me. In these neighbourhoods, gangs are allowed to run riot, terrorising the innocent while the police stay safely away.
2. If something such as imagination or speculation runs riot, it expresses itself or spreads in an uncontrolled way. My imagination ran riot, visualising late nights and weekend parties. We have no proof and when there is no proof, rumour runs riot. Note: In hunting, if the hounds run riot, they follow the scents of other animals rather than the one they are supposed to be chasing.