go over sb's head
to speak to or ask permission from someone who has more authority than the person who you would normally go to in that situation:
Amanda was refusing to give me the week off so I went over her head and spoke to the boss.

[TahlilGaran] Advanced Learner's Dictionary ▲

go over head
go over (someone's) head
1.
to deal with someone at a higher level.
I would occasionally go over my manager's head to complain to the top financial officer.

2.
to fail to understand something.
She was being sarcastic, but he took her seriously — the joke totally went over his head.

[TahlilGaran] English Idioms Dictionary ▲

go over head
to be too difficult for someone to understand
The explanation of how to operate the machinery went over my head.

The reasons for the decision went over my head. I could not understand why.

[TahlilGaran] English Idioms Dictionary ▲

go over someone's head
go over (someone's) head
1.
to deal with someone at a higher level.
I would occasionally go over my manager's head to complain to the top financial officer.

2.
to fail to understand something.
She was being sarcastic, but he took her seriously — the joke totally went over his head.

[TahlilGaran] English Idioms Dictionary ▲

go over someone's head
to be too difficult for someone to understand
The explanation of how to operate the machinery went over my head.

The reasons for the decision went over my head. I could not understand why.

[TahlilGaran] English Idioms Dictionary ▲

go over one's head
v. phr.
1. To be too difficult to understand.
Penny complains that what her math teacher says simply goes over her head.
2. To do something without the permission of one's superior.
Fred went over his boss's head when he signed the contract on his own.

[TahlilGaran] English Idioms Dictionary ▲