school burglary; school vandalism
Refers to breaking into a school to steal or vandalize. Often used in news reports.
昨夜、近所の小学校で学校荒らしがあった。
There was a school burglary at the nearby elementary school last night.
警察は学校荒らしの犯人を捜している。
The police are searching for the perpetrator of the school vandalism.
Compound of 学校 (school) and 荒らし (act of breaking in or vandalizing, from the verb 荒らす).