吹水 (chui sui), v. Cantonese slang. To chat, bullshit.
“Shut up/get lost.”
A group of four gamblers playing Fan Tan is a “skin.”
When police broke up illegal gambling dens, this cry would go out as a warning.
Has since become an insult.
An alternative origin derives from “withdraw foreskin,” i.e. “stop having sex and leave.”