over somebody's head

Từ điển Oxford Advanced Learner 8th

over sb's ˈhead idiom
1. too difficult or complicated for sb to understand
•A lot of the jokes went (= were) right over my head.
2. to a higher position of authority than sb
•I couldn't help feeling jealous when she was promoted over my head.
•I'm not happy that you went over my head to ask for this time off.
Main entry: ↑head_idiom