搖頭晃腦 [摇头－脑]

Jyutping jiu4 tau4 fong2 nou5
Pinyin yáo tóu huàng nǎo

Definitions (CC-CANTO)
  1. wagging one's head smugly, looking pleased with oneself (self-conceit)
Definitions (Wiktionary)
  1. phrase, idiomatic
    to wag one's head; to look pleased with oneself; assume an air of self-approbation/self-conceit
Definitions (Kaifangcidian)
  1. （沒有對應漢語詞彙）