烏矸仔貯豆油 [乌－－贮－－]

Jyutping wu1 gon1 zi2 cyu5 dau2 jau4
Pinyin wū gān zǎi zhù dòu yóu

Definitions (Wiktionary)
  1. phrase, Hokkien, figuratively, idiomatic
    to be a hidden talent