المعنى الاصطلاحي

It is when a man marries his daughter, or any other woman under his guardianship, to another man on the condition that the latter will marry him to someone under his guardianship, with or without a dowry.

الشرح المختصر

"Nikāh ash-shighār" (exchange marriage) is one of the invalid marriages that was widespread during the pre-Islamic era. It is when a man marries a woman under his guardianship, whether she is his daughter, sister, mother or anyone else, to another man on the condition that the prospective husband marries him to his daughter, sister, mother, etc. Assuming there is a fixed dowry in such a situation, it will not make the marriage any less invalid. It has been called "shighār" (empty) because it is a practice void of any trust or justice; or because of the resemblance, in being despicable, of a dog lifting his leg to urinate, which is as ugly as swapping one woman for another. Harms of "nikāh ash-shigār": 1. Forcing women to marry against their will, which gives preference to the guardian's own interest over that of the woman's. 2. Betraying the trust placed on guardians represented in choosing an equal suitor for the woman, because the guardian will look out for his own interest and desires and disregard those of the woman. 3. Depriving women of the dowries completely or dowries similar to their peers. 4. It leads to quarrels and disputes after marriage, and this is from the immediate repercussions of opposing the Islamic law.

التعريف

That one man gives another his own daughter or sister in marriage in return for the other man giving him his own daughter or sister to marry, without either woman receiving a dowry.