Force resistance, sometimes called Force immunity, referred to several applications of the Force used to defend against Force powers.
In its most basic definition, Force resistance referred to the resilience that a Force-user exhibited against Force abilities. Since this defense could be overcome by an opponent's superior willpower and mastery of the Force, the Jedi could learn to generate an aura providing additional protection against physical and mental Force powers. Such a technique was also known as Force resistance at the novice level, but mastery of it was ascribed the name Force immunity as its user could render some Force powers entirely inert.
As one of the first lessons taught by members of the Jedi Order, Force-sensitives learned to use the Force to negate the effects of the dark side of the Force on one's mind by imagining an impenetrable fortress within one's mind.
Specialized combat against the dark side was the domain of the Jedi Sentinels, and consequently, their training revolved heavily around developing Force immunity against it. The Force immunity of a Sentinel, once mastered, could afford them absolute, passive invulnerability to powers that induced fear, disorientation, loss of senses, and even outright paralysis. Such a feat was attained by cultivating a connection with the Force so unshakable that the Sentinel would virtually become one with it.
One application of the shielding technique was to negate the effects of the dark side felt by light side users when they were nearby powerful dark side objects such as Lignan ore. By 5000 BBY, the technique was one of the most common skills that was taught to Jedi in the Jedi Order, and it had been passed down for many generations. Imar Deez taught this technique to Relin Druur, who in turn taught it to Drev Hassin and Marr Idi-Shael. Revan used similar power to resist the Sith Emperor during his captivity.