大懵鬼 [－－－]

Jyutping daai6 mung2 gwai2
Pinyin dà měng guǐ

Definitions (CC-CANTO)
  1. noun; derogatory word, describes someone who is confused; muddle-headed, stupid
Definitions (粵典–words.hk)
  1. 名詞
    經常​唔​記得​嘢​、​唔​醒目​嘅​人
    an idiot, literally "big stupid ghost"