1.
to be unable to hold one's head up before someone; to be no match for
To feel unable to assert oneself in front of someone because of a debt of gratitude, their authority, or one's own past failings; literally 'one's head does not rise', as in a permanent bow. The person is marked with に: 妻には頭が上がらない.
I still can't hold my head up before the senior who looked after me back then.
Literally 'one's head does not rise': the image is of a bow one can never come up from. The person is marked with に, usually には.
Common patterns
Usage
Said of a spouse, a benefactor, a former teacher, or anyone whose help or authority leaves one permanently in the weaker position. Often half-joking, especially about one's wife or husband.