Deutéronome 23:18

You shall not profane your daughters to make them harlots; nor shall any man of Israel debase himself by fornication.

The passage involving a prostitute comes next, because of the connection through the male slave. The Exegetes of our religion have asserted [Sanhedrin 54b] that a male prostitute denotes a catamite (as evidenced by the preposition from the sons of Israel). Moreover, when Elihu said “…and their life as that of the male prostitutes” [Job 36: 14], the word “their soul” was parallel to “their life”, and thus the word “male prostitutes” was parallel to “youth”. In addition, there are the verses “there was male prostitution in the land” [I Kings 14: 24], and “the houses of the male prostitutes” [II Kings 23: 7] (where the latter are distinct from the “women”, who were “weaving there”). I do not understand the etymology of the word prostitute . However, when one inquires thoroughly into the meaning of the word, it becomes clear that it denotes a woman who is receptive to any man (this is evidenced by “where is the prostitute?” [Genesis 38: 21]). If so, then a male prostitute is someone who performs the acts of the Egyptians — verbum sat sapienti. After mentioning harlotry, Scripture then proceeds to discuss

THERE SHALL BE NO ‘K’DEISHAH’ OF THE DAUGHTERS OF ISRAEL — “one who is devoted to and always prepared for illicit intercourse. NOR SHALL THERE BE A ‘KADEISH’ OF THE SONS OF ISRAEL — one who is always prepared for pederasty.” This is Rashi’s language. Now, if this prohibition constitutes an admonition against the woman so engaged and warns her against being “devoted to and always prepared for illicit intercourse,” then an unmarried woman who has [illicit] intercourse with a man unpremeditatedly and secretly is not among those guilty of transgressing a negative commandment! So also in the matter of the kadeish, why did Rashi mention that he is devoted to “and always prepared” [for such sin] — even one who permits himself to be so abused in an innermost chamber is guilty of extirpation [if there are no witnesses] and death by the court [if there are witnesses]! Moreover, it would have been proper for Scripture to state, “There shall not be among you a k’deishah, nor shall there be among you a kadeish,” for the expressions of the daughters of Israel and of the sons of Israel make it appear that the verse discusses another nation!
It appears to me concerning this prohibition that it constitutes an admonition addressed to the members of the court that they should not permit one of the daughters of Israel to sit in public view at the crossroads for the purpose of illicit intercourse, or prepare herself a tent of prostitution as is customary in foreign lands where they sit at the door with timbrels and harps, similar to what is written, Take a harp, go about the city, thou harlot long forgotten; make sweet melody, sing many songs, that thou mayest be remembered. And similarly Scripture warns the court concerning a kadeish. And in line with the plain meaning of Scripture, even if he should lie with women in a tent which he prepared himself for such illicit relations or that he should sit in public view at the crossroads [on the lookout for such women], he warned the court [against permitting such activities].
It appears to me that such is the opinion of Onkelos [who rendered the verse: “A woman of the daughters of Israel shall not become the wife of a slave, and no man of Israel shall marry a bondwoman”]. is one who is devoted to, and always ready for illicit intercourse” is different from that of Onkelos. The same is with regard to a kadeish. But he [Onkelos] combined with this prohibition the …

קדשה, a harlot; an unmarried woman engaging in adultery (with a married man)

קדש, a male sleeping promiscuously with women without bothering to marry them. Since the women in question do not sleep with him exclusively they are not even concubines.