Is it permissible to engage in nikah (sexual intercourse without a marriage contract) with polytheist, atheist, immodestly dressed women, given that they do not meet the conditions for which zina (fornication/adultery) was prohibited (violation of honor, mixing of lineages)?

Adultery is one of the gravest sins, and there is no disagreement regarding its prohibition, whether it is committed with a Muslim woman or a disbeliever, or whether it results in the violation of honor or the mixing of lineages or not. Scholars have mentioned that among the wisdoms behind the prohibition of adultery are: the violation of honor and the mixing of lineages. Many diseases have emerged because of it, and time may reveal other harms, in fulfillment of the words of Allah Almighty: "We will show them Our signs in the horizons and within themselves until it becomes clear to them that it is the truth. Is it not sufficient concerning your Lord that He is, over all things, a Witness?" (Fussilat: 53).