一問三不知 (jat1 man6 saam1 bat1 zi1) — ask a person about something and he will tell you that there are actually three things he doesn't know anything about (said of people who do not wish to give out information or cooperate) in Cantonese
jatˉ¹一manˍ₆問saamˉ¹三batˉ¹不ziˉ¹知简 一问三不知
Mandarin Pinyin: yi1 wen4 san1 bu4 zhi1
Meaning of 一問三不知
nounask a person about something and he will tell you that there are actually three things he doesn't know anything about (said of people who do not wish to give out information or cooperate)