Meaning of “MizuShoubai(水商売)”

“MizuShoubai(水商売)” means business which depends on how popular is it, basically.
So service industry and entertainment business are “MizuShoubai(水商売)”.
“Mizu(水)” means water, “Shoubai(商売)” means business.
The future of the businesses are unpredictable like water flow which is changing always.

Otherwise, “MizuShoubai(水商売)” also means sex industry / people.
In this case, hostess of the bar charged per hour (I’d like to mention cabacla(キャバクラ)) or other hostess of more sexy somewhere are “MizuShoubai(水商売)”.

Example Conversation

A: I broke up with my girlfriend yesterday…
B: What? Why?
A: She worked at “MizuShoubai(水商売)”…
B: If it’s just cabacla(キャバクラ), I think it’s OK.
A: She worked at brothel…
B: Oh…

A: 昨日彼女と別れた
B: まじで？なんで？
A: 水商売やってたんだってさ…
B: キャバクラ程度ならよくない？
A: 風俗だよ…
B: あー…