القاهر
كلمة (القاهر) في اللغة اسم فاعل من القهر، ومعناه الإجبار،...
Sale of money for money, whether they are of the same kind or different such as dirhams, dinars, and banknotes.
"Bay‘ as-sarf" (sale of money for money) is defined by the majority of jurists as the sale of something that is a price for something that is also a price, whether they are of the same kind or not. It includes the sale of gold for gold, silver for silver, or gold for silver. It is called "sarf" due to the need for exchanging it hand to hand.