胸大無腦 [－－无脑]

Jyutping hung1 daai6 mou5 nou5
Pinyin xiōng dà wú nǎo

Definitions (CC-CEDICT)
  1. (having) big boobs but no brain
  2. bimbo
Definitions (Wiktionary)
  1. phrase, idiomatic, slang
    big-breasted, but small-brained; big-breasted bimbo