blackboard jungle

noun Informal.

a school or school system characterized by lack of discipline and by juvenile delinquency.

Origin of blackboard jungle

1950–55; on the model of asphalt jungle; popularized by the novel of the same name (1954) by American author Evan Hunter (born 1926) Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019