勞豆殼子神 [劳－壳－－]

Jyutping lou4 dau6 hok3 zi2 san4
Pinyin láo dòu ké zǐ shén

Definitions (Wiktionary)
  1. verb, Xiang
    to bother one's head for nothing
    (syn.) 白费心思, 勞空神, 白費心思, 劳空神