腦筍未生埋 [脑笋－－－]

Jyutping nou5 seon2 mei6 saang1 maai4
Pinyin nǎo sǔn wèi shēng mái

Definitions (CC-CANTO)
  1. (one's fontanelles are not closed); immature; childish
Definitions (Kaifangcidian)
  1. 幼稚
  2. 不懂事
  3. 少不更事
  4. 沒腦筋 – 没脑筋