Arabic (بيع باطل) for void sale (void contract/ transaction of sale). It is a type of ba’i (belonging to the category of buyu muharramah/ buyu batilah) that doesn’t fulfill the conditions/ requirements relating to its elements and/ or involves certain impermissible attributes or shari’ah violations (riba, excessive gharar, etc.)

An example of ba’i batil is bai al-tanajush (ba’i al-najsh) in which a person or group of persons connive with a seller to bid up the price of a commodity offered for sale through an auction (mazad), not meaning to purchase but only to entice an unsuspecting bidder to offer higher prices, and eventually have him stuck with the object of sale. The ensnared buyer will have to pay an artificially determined price (a much higher price than fair or normal price).

Ba’i al-tanajush is an Arabic term that translates as a sale by a fraudulent auction or sale by a manipulative overpricing. This sale is based on collusion (tawatu’) between a seller and a fake (ghost) bidder.