קודם מתן תורה היה אדם פוגע אשה בשוק אם רצה הוא והיא נותן לה שכרה ובועל אותה על אם הדרך והולך. וזו היא הנקראת קדשה. משנתנה התורה נאסרה הקדשה שנאמר לא תהיה קדשה מבנות ישראל. לפיכך כל הבועל אשה לשם זנות בלא קידושין לוקה מן התורה לפי שבעל קדשה:
Before the Torah was given, when a man would meet a woman in the
marketplace, and he and she desired, he could give her payment, engage
in relations with her wherever they desired, and then depart. Such a
woman is referred to as a harlot.
When the Torah was given, [relations with] a harlot became forbidden,
as [Deuteronomy 23:18] states: "There shall not be a harlot among the
children of Israel." Therefore, a person who has relations with a
woman for the sake of lust, without kiddushin, receives lashes as
prescribed by the Torah, because he had relations with a harlot.
Interestingly enough, while you are subject to lashes for engaging in intercourse with a gentile prostitute, the Talmud permits eating at her table and drinking wine in her abode:(Avodah Zarah 70A)§" Rava says: In the case of a gentile prostitute, where Jews are dining at her table, the wine at the table is permitted. Granted, their passion for the sin of harlotry overwhelms their judgment". So visiting a foreign gentile prostitute appears to be permitted, provided you don't hire her services.