noun
making a living in the red-light district
Refers to earning one's livelihood through work in the sex industry or entertainment quarters. The term carries a somewhat gritty or unsavory connotation, evoking the image of working in 'muddy waters.'
彼は若い頃、泥水稼業で生計を立てていた。
In his youth, he made a living in the red-light district.
水商売 is a broader term for nightlife and entertainment trades, including bars and hostess clubs, while 泥水稼業 specifically emphasizes the grittier, more stigmatized side of sex work.
Compound of 泥水 (muddy water) and 稼業 (trade, livelihood). The 'muddy water' metaphor suggests a morally or socially murky line of work.