From Longman Dictionary of Contemporary Englishgo over somebody’s headgo over somebody’s headUNDERSTAND a) to be too difficult for someone to understand The explanation went completely over my head. b) to do something without discussing it with a particular person or organization first, especially when you should have discussed it with them → head
Examples from the Corpus
go over somebody’s head• His enormous arm went over Rory's head, the empty pint pot hanging in the smoke above the counter.• Could he go over the heads of Congress and get the country behind him?• He says that the bid is hostile because it goes over the heads of the directors.• Mrs Singh seemed to be listening intently but I guess that a lot of what was being said went over her head.• The more emotional scenes go right over the kids' heads.• Are we going to get Blagg or do we go over your head?• They worried that the experienced subordinate would go over their head and gain support from their superiors. 