Head Fake is a sports term used when a player moves their head to fake a change in direction.[1]
In market trading a head fake is where the market appears to be moving in one direction but ends up moving in the opposite direction.[2] For example, the price of a stock may appear to move up, and all indications prior to that are that it will move up, but shortly after reverses direction and starts moving down.
Head fakes are often caused by market makers who place bids and asks in such a way that they cause the apparent (fake) trend in order to later profit from it.
In his "Last Lecture", titled "Really Achieving Your Childhood Dreams" (at Carnegie Mellon on September 18, 2007), Randy Pausch extensively refers to "head fakes" during his speech.