悶騷 [闷骚]

Jyutping mun6 sou1
Pinyin mēn sāo

Definitions (CC-CEDICT)
  1. (coll.) outwardly cold or retiring but deep and passionate inside
Definitions (Wiktionary)
  1. adj, neologism, of personality
    having a smouldering sexuality; sultry; restraining oneself in appearance but abounding in fervour inside