挂上号

Traditional (Taiwan): 掛上號

guàshànghào ㄍㄨㄚˋ ㄕㄤˋ ㄏㄠˋ

    • to be registered or entered on a list
    • to be recorded as belonging to a group

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
get one's number hung up (registered)
Meaning
To be entered on a list or recorded as belonging to a group; the image comes from registering to see a doctor. Neutral.

Sources