Najash

The prohibited practice of deceiving and inciting a potential buyer during the course of pre-sale negotiations or bidding by egging him on, either through insincere bidding on the part of a spectator (such as bidding with no intention of buying and merely in order to have the would-be buyer raise his bid), or false statements on the part of the seller himself (such as the seller claiming that the commodity is of greater value than its true worth).