monkey business

Translations
шалости, проделки
The kids were up to some monkey business while their parents were away.
Дети занимались шалостями, пока их родители были в отъезде.
Definitions
Monkey business refers to playful or mischievous behavior, often implying that someone is engaging in silly or deceitful activities rather than serious or productive work.
Words
monkey

noun
обезьяна
business

noun
проделки