"Hedging" is a strategy used in gambling and fantasy scenarios to describe protecting a bet against a greater risk by doing something that may seem counterintuitive.
In fantasy football, hedging often means starting a player that may work in tandem with a player your opponent is starting, even if it means both players will likely depend upon each other. This is designed to ensure your team will earn at least a marginal victory against your opponent.
Hedging can be a great strategy if used correctly. Many players set their lineups and overthink the effect of hedging. Hedging should be used when the correlation between two players is strong and the hedger is already winning.
The classic example of hedging against an opponent's lineup is starting a quarterback even though your opponent has a wide receiver on the same team. In this scenario, it is extremely unlikely that the receiver will score without his quarterback scoring as well.
An example of intra-team hedging is starting both offensive players and a defense that are playing against each other in real life. This is counterintuitive because the success of the offense and defense that are opposing each other rely on the detriment of the other.
Setting a lineup in a certain way can also be used to hedge success relative to one's biases. Starting a lineup consisting solely of players from a favorite team might make a big win even better, but a loss would become substantially worse. Hedging by using a variety of players from loved and hated teams is a common strategy for separating emotions and biases from one's fantasy team.