Courtesan, mistress, madam and pimp are old words that still turn up in adverts and in searches. Each has a historical meaning and a different meaning today, and one of them describes a criminal offence.
Courtesan
A courtesan was a woman, usually well educated, who was the companion of wealthy or powerful men, in the courts of Renaissance Venice and in eighteenth and nineteenth century France and England. The role was prized for conversation, taste and discretion as much as for sex. Today the word is used to romanticise high end escorting, and an advert that uses it is describing a style, not a licence. High class escorts covers what such phrases do and do not guarantee.
Mistress
Traditionally a woman in a long term relationship with a man who is married to someone else. In adverts, Mistress is also a title used by a dominatrix, as in “Mistress Name”, and has nothing to do with the first meaning. What is a dominatrix? explains the role.
Madam
A polite form of address, and, historically, the woman who ran a brothel or an agency. Today the word usually means the manager of an escort agency. An agency that introduces clients to workers who remain in charge of their own work is lawful. One that controls their hours, their money or their activities for gain risks the offence below.
Pimp
Someone who controls another person’s prostitution for gain. In England and Wales that is an offence under section 53 of the Sexual Offences Act 2003, with a maximum of seven years. It is not the same thing as an agency that takes a fee for a booking, and the difference is control. If you think someone is being controlled, safety and help has the contacts.
Related words
Escort versus prostitute covers escort, prostitute, sex worker and call girl, and what is a brothel covers the premises.