壽頭壽腦 [寿头寿脑]

Jyutping sau6 tau4 sau6 nou5
Pinyin shòu tóu shòu nǎo

Definitions (CC-CANTO)
  1. a silly and inexperienced person who always gets cheated by others
Definitions (粵典–words.hk)
  1. 形容詞、俚語
    烚​下​烚​下​；​傻傻​哋
    muddle-headed, foolish
  2. 近義詞
    傻頭傻腦
Definitions (Wiktionary)
  1. phrase, Wu, especially, idiomatic
    slow and stupid
    (syn.) 呆头呆脑, 傻裡傻氣, 呆頭呆腦, 傻里傻气
Definitions (Kaifangcidian)
  1. 呆頭呆腦 – 呆头呆脑
  2. 傻頭傻腦 – 傻头傻脑