不显山不露水

Traditional (Taiwan): 不顯山不露水

bùxiǎnshānbùlùshuǐ ㄅㄨˋ ㄒㄧㄢˇ ㄕㄢ ㄅㄨˋ ㄌㄨˋ ㄕㄨㄟˇ

    • lit. to not show the mountain and to not reveal the water (idiom) fig. to hide the key facts

Character by character

Saying俗语俗語

Idiom惯用语 · Widely known

Literally
not showing the mountain, not revealing the water
Meaning
Keeping one's abilities, intentions or secrets hidden; staying low-key. Neutral to slightly wary.

Sources