mischief

1. (uncountable) Conduct that playfully causes petty annoyance.Examples: "Drink led to mischief."Synonyms: delinquency, naughtiness, roguery, scampishness, atrociousness, awfulness, badness, corruptionuncountable

2. (countable) A playfully annoying action.Examples: "John's mischief, tying his shoelaces together, irked George at first."countable

3. (collective) A group or a pack of rats.Examples: "Kirac, the leader of the rats under his charge, speaks to the major through his telepathic abilities that manifested after the alien virus infected him and his mischief of rats."; "A group of rats is not a herd or a gaggle, but a pack or a mischief of rats. Rats in general are omnivorous, meaning they will eat almost anything."collectivecountableuncountable

4. (archaic) Harm or injury:Examples: "She had mischief in her heart."; "Sooner or later he'll succeed in doing some serious mischief."; "Was I the Cauſe of Miſchief, or the Man / Whoſe lawlesſ Luſt the bloody War began?"archaicuncountable

5. (archaic) Harm or injury:Examples: "It may end in her doing a great mischief to herself—and perhaps to others too."; "[R]eligion / Hides many mischiefs from suspicion."; "I will heape mischiefes vpon them, I will spend mine arrowes vpon them."archaiccountable

6. (law) A criminal offence defined in various ways in various jurisdictions, sometimes including causing damage to another's property.countableuncountable