riot

1 noun

1 (C) a situation in which a large crowd of people are behaving in a violent and uncontrolled way especially when they are protesting about something: The army were called in to put down the riot. | race riot (=between people of different races): Ethnic tensions led to a massive race riot.

2 a riot of colour something with many different bright colours: The garden is a riot of colour in May.

3 run riot

a) if people run riot, they behave in a violent, noisy, and uncontrolled way: Demonstrators are running riot through the town.

b) if your imagination, thoughts etc run riot, you cannot control them

c) if a plant runs riot, it grows very quickly

4 read (sb) the riot act often humorous to give someone a strong warning that they must stop causing trouble: If the kids don't settle down soon, I'll go up and read them the riot act.

5 (singular) old-fashioned someone or something that is very funny or enjoyable: Sally's a riot when she's had a few drinks! | have a riot (=have a lot of fun): “How was the party?” “Oh, we had a riot!”

2 verb (I) if a crowd of people riot, they behave in a violent and uncontrolled way, for example by fighting the police and damaging cars or buildings: Students were rioting in the streets. — rioting noun (U) — rioter noun (C)