瓦上霜

wǎshàngshuāng ㄨㄚˇ ㄕㄤˋ ㄕㄨㄤ

    • something or someone that will soon vanish

Character by character

Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
frost on the tiles
Meaning
Something or someone that will soon vanish.

Sources