Hanzi of "chui"

[Matt]

Does anyone know the hanzi for the word "chui" which has the connotations of disapproval. Something like "pssh" in English. Perhaps it's more like "choy" then "chui" I'm not sure. But any feedback?

[Terence]

guess

coi1 Ԫ. someone has said something inproper, deemed to be causing bad luck, Cantonese will say coi1 to reverse it or diverse the bad things away. but the character alone has no meaning.