An Arabic term (نجش) which literally means concealment or a practice in which hunters used to rouse and chase the game for the sole purpose of trapping or snaring it. In the context of commercial transactions, najsh (also misspelled as najash) has a similar meaning, with the game being replaced with an unsuspecting buyer. In other words, it is a deceptive practice in auctions whereby the seller attempts to sell an object/ article for more than its fair price by conspiring with fake bidders that they bid up the price to ensnare a buyer. As such, the buyer will get stuck to the transaction while the fake bidders retreat unnoticed.

In modern day conventional transactions, there are many actions that fall under najash, including: pump and dump, hype and dump, creating fake demand or supply, etc.