Puff is the colloquial, often derogatory term for a brothel, a salon or an establishment in which sex work is offered. The term comes from the Red Welsh "puffen" (= to work noisily) or the Low German "Puff" (= Stoss).
In professional industry discourse (authorities, sex workers, advice centers), "Puff" is avoided - instead the terms Salon (smaller business with independent sex workers), Etablissement (medium-sized business with a license), or are used Brothel (classic term in legal and police jargon).
In the tabloid media, "whorehouse" has a permanent place in headlines - usually in the context of scandals, noise disputes or police raids.