Commentary for Genesis 38:21

הקדשה— means a woman who is devoted to, (מקדשת) and who is ever ready for illicit intercourse.

הקדשה, the harlot; a woman who is always ready to have sexual relations with any male. The male equivalent of the term is found in Deuteronomy 23,18. where the Torah instructs the Jewish people not to tolerate this phenomenon, and in Kings I 14,24 where the presence of such male prostitutes is acknowledged with the words וגם קדש היה בארץ, a phenomenon which surfaced immediately after the death of King Solomon.

וישאל..אנשי מקומה, in the alley where she lived. Yehudah must have asked her for her address; how else could he expect to redeem the items he had left with her? She had therefore named a certain alley as her address. When Chirom came there to seek her out at the address she had given Yehudah, and he did not see a harlot in that alley, he asked people of the alley if they knew where the harlot was who had been plying her trade at the road junction. The local residents told him: לא היתה בזה קדשה, that in that location there had not been any prostitute. Both the words בזה and מזה occur in the Torah as references to locations, as we know already from 37,17.

The cult prostitute [hakedeisha; הקדשה]. A woman available/prepared for sex, as in "purify yourselves [hitkadshu; התקדשו] for tomorrow" (Bamidbar 11:18).