muck about

Từ điển Oxford Advanced Learner 8th

ˌmuck aˈbout/aˈround derived
(BrE, informal)to behave in a silly way, especially when you should be working or doing sth else
Syn: ↑mess about
•I spent most of my time at school mucking about and getting into trouble.
Main entry: ↑muck_derived