noun, noun which may take the genitive case particle 'no'
over someone's head; bypassing; without consultation
Describes an action taken without involving or informing the person who should normally be consulted, often implying a breach of hierarchy or protocol. Commonly used with verbs like する, 決める, 話す, 交渉する.
上司の頭越しに部長と直接交渉した。
I negotiated directly with the department head, bypassing my boss.
彼は私の頭越しに重要な決定を下し
He made an important decision over my head.
Compound of 頭 (あたま, 'head') and 越し (ごし, 'over, across'), literally 'over the head'. The figurative sense of bypassing someone in authority or consultation is a natural extension of the spatial meaning.